First time posting here and It's a rant so no need to read the whole thing! I just need to get things off my chest...
I work at a second-hand shop. 
I'm 20 and finding a job after finishing high school was a nightmare.
Sending CVs, going to job interviews and generally not hearing answers from companies was stressful.
But then I landed this job at this shop that I do regularly visit and was happy that at least I was going to work somewhere close to home and with a nice pay.
At first things were going well then I made mistakes such as placing wrong price tags on items that had a much higher value than what I gave them or giving them a lot of value even if they weren't of good quality.
My boss told me that it is alright to make mistakes, but that I also needed to become faster and better at my job.
At first, she was understanding of my clumsiness.
This was my first job and I didn't have any previous experience.
But after a few months, my boss told me that I still wasn't fast enough and that when I selected items I still wasn't giving them the right prices.
She told me things that only my colleague knew about and at this point I was feeling pretty overwhelmed.
I started panicking...I needed to be faster and better but I didn't know how.
When my boss scolded me again about some prices, I nearly went into a panic attack.
I calmed myself, but for the rest of the day I just couldn't wait to get home and go to sleep...
My boss told me that my job isn't a game (and I never treated it as such) so I wasn't sure about anything I learned at that point.
I started asking more questions about the prices and even now I always ask if I'm uncertain about something.
My colleague just rolls her eyes at this point and I hate the fact that I'm not fast and good at the job.
Or that I didn't learn as much as my boss wanted...
Everytime I go to work I get nervous, my heart starts beating fast and I nearly choke on my saliva.
My boss noticed my anxiety and told me that I shouldn't get defensive when she is giving me advice and that before calming myself before a panic attack or when I feel overwhelmed to listen to what she has to say about my work performance.
She is right to say this. Mistakes are a normal part of a job if you don't have any prior experience, but the way they word it makes me feel utterly horrible.
She told me to not take things at heart, but then the next minute she says that I shouldn't justify the way I do the job and only to listen to her and my colleague...
When I get items that need to be valued I get nervous now.
My doctor gave me some medication to stay calm and to help with my anxiety, but then I find myself being too slow or sloppy at work.
Uh, sorry.
This is such a mess and I just want to reach old age and be at peace...
If you read through all of this thank you so much!! 
I hope that you all have a nice day/night wherever you are!!!!