A survivor of the Boston Marathon bombing has posted an open letter to bomber Dzhokhar Tsarnaev on her Facebook page, just hours after testifying on the first day of the 21-year-old's trial. Rebekah Gregory, 27, from Houston, Texas, lost half of her left leg after 18 surgeries following the April 15, 2013 blast. She and her 5-year-old son, Noah, had been watching her boyfriend's mother compete in the race when the explosion occurred. Scroll down for video . Rebekah Gregory, pictured left in a courtroom sketch from Wednesday, who lost half of her left leg as a result of the bomb, wrote a lengthy Facebook post in which she said seeing Tsarnaev in court had helped her realize she isn't afraid anymore . On Wednesday night she wrote a lengthy post in which she said seeing Tsarnaev in court had helped her come to terms with what happened that fateful day. 'TODAY...I looked at you right in the face....and realized I wasn't afraid anymore,' Gregory wrote. 'And today I realized that sitting across from you was somehow the crazy kind of step forward that I needed all along.' The emotional letter has been shared more than 2,500 times and received over 11,000 'likes' within hours of being posted. Earlier Ms Gregory had told the court that the last thing she remembered before the explosion was entertaining Noah who was bored watching the runners. She said that the force of the blast had thrown her backwards and immediately she began looking for her son - but realized she had bones sticking out of her legs and arms and flesh hanging from her body. 'My bones were lying next to me on the sidewalk,' Gregory recalled during her testimony in federal court in Boston. 'I felt that was the day I would die.' Ms Gregory's boyfriend Pete DiMartino, 30, was also present at the bombing and suffered a shattered ankle, a ruptured eardrum, and lost his right Achilles tendon in the blast . She told the court that she could hear Noah screaming 'mommy' and asked God to take her but not her son. Ms Gregory began to weep as she said that as she scanned for Noah, she saw the body of Krystle Campbell lying behind her. She recalled that an emergency responder told her she was going to be OK then yelled: 'We have an amputee!' Several jurors were close to tears as Ms Gregory told the court that she still has shrapnel in her body and each time a piece works its way to the surface, she will have an operation. Her son Noah suffered a shrapnel injury to his leg and head. Ms Gregory was shown a photo in court in which she was able to identify herself and her family with bomber, Tamerlan Tsarnaev, standing directly behind. Ms Gregory's boyfriend Pete DiMartino, 30, was also present and suffered a shattered ankle, a ruptured eardrum, and lost his right Achilles tendon in the blast. The couple announced last month that they have separated after just 10 months of marriage. Gregory and DiMartino announced last month that they have separated after just 10 months of marriage, left, while Dzhokhar Tsarnaev is on trail for his role in the marathon blast on April 15, 2013 . Despite getting married and staying together as Gregory had her leg amputated, the couple have decided to part ways citing irreparable strain, The People reported. Gregory, who struggled her way down the aisle after learning to walk again following the amputation, told The People: 'After the decision was made to amputate my leg in November, I found myself having to make an even more painful choice – to separate from my husband Pete. 'Over the last several months I've come to realize that going through such a horrific event together put a fast-forward on our relationship that we each handled differently. 'While my heart is beyond broken, I have a certain peace knowing from day one, I truly gave it my all, and have been fully invested in keeping this marriage, and my commitment before God. 'I still love Pete with all of my heart and ask that everyone respect our privacy as we try to figure out our next steps. 'As for now, I am focused on doing what I feel is best for my son and I, and will concentrate my time on healing, both physically and emotionally.' The couple had a fairytale wedding, documented on the season finale of TLC's popular reality show, Say Yes To The Dress. They wed in Asheville, North Carolina, in April last year then moved to Houston, Texas. Seeing Tsarnaev in court had helped her realize she isn't afraid of him anymore, wrote Rebekah Gregory . Dear Dzhokhar Tsarnaev, . My name is Rebekah Gregory. We don't really know each other and never will. But over the last two years, I have seen your face not only in pictures, but in almost every one of my nightmares. Moments before the first blast, your stupid backpack even brushed up against my arm, but I doubt you remember because I am no one to you. A complete stranger. And although I was merely just a blip on your radar, (someone that happened to be standing 3 feet from your designated 'good spot' for a bomb), you have been so much more to me. Because you have undoubtedly been my source of fear since April 15th, 2013. (After all, you are one of the men responsible for nearly taking my child, and for the permanent image embedded in my brain of watching someone die.) Up until now, I have been truly scared of you and because of this, fearful of everything else people might be capable of. But today, all that changed. Because this afternoon, I got to walk into a courtroom and take my place at the witness stand, just a few feet away from where you were sitting. (I was WALKING. Did you get that?) And today I explained all the horrific details, of how you changed my life, to the people that literally hold YOURS in their hands. That's a little scary right? And this afternoon before going in, I'm not going to lie..my palms were sweaty. And sitting up there talking to the prosecution did make me cry. But today, do you know what else happened? TODAY...I looked at you right in the face....and realized I wasn't afraid anymore. And today I realized that sitting across from you was somehow the crazy kind of step forward that I needed all along. And I think that's the ironic thing that happens when someone intends something for evil. Because somehow, some way, it always ends up good. But you are a coward. A little boy who wouldn't even look me in the eyes to see that. Because you can't handle the fact that what you tried to destroy, you only made stronger. And if your eyes would've met mine for just one second, you would've also seen that what you 'blew up' really did BLOW UP. Because now you have given me (and the other survivors) a tremendous platform to help others, and essentially do our parts in changing the world for the better. So yes...you did take a part of me. Congratulations you now have a leg up...literally. But in so many ways, you saved my life. Because now, I am so much more appreciative of every new day I am given. And now, I get to hug my son even tighter than before, blessed that he is THRIVING, despite everything that has happened. So now...while you are sitting in solitary confinement, (awaiting the verdict on your life), I will be actually ENJOYING everything this beautiful world has to offer. And guess what else? I will do so without fear....of YOU. Because now to me you're a nobody, and it is official that you have lost. So man that really sucks for you bro. I truly hope it was worth it. Sincerely, . Someone you shouldn't have messed with . ‪#‎bostonstrong .
Rebekah Gregory, 27, wrote that seeing Tsarnaev in court had helped her realize she isn't afraid of him anymore . Her lost half of her left leg after 18 surgeries following the April 15, 2013 marathon blast . 'Today I realized that sitting across from you was somehow the crazy kind of step forward that I needed all along,' she wrote . Earlier in the day in court she had wept as she recalled seeing a death body in the aftermath of the deadly blast .