Hi Reddit, this is my first post in the Anxiety community of reddit. I've been lurking for months, though, and I need advice. Badly.  
Lately I have been experiencing crippling anxiety (both health anxiety and general anxiety). I just had a breakdown about 30 minutes ago thinking about the future.  
I am so UNBELIEVABLY terrified of the future. I am currently dating a beautiful girlfriend, who I love, and I have an amazing family. I'm going to marry my girlfriend one day, probably some day soon (I'm 21), and I am horrified of one day losing her.  
I'll outright say it: I am terrified of watching her, one day, pass away before I do. I don't want to marry someone and live my life with someone just for them to pass away and leave me all alone. This is so ridiculously frightening to me. I've had thoughts like these before in the past for my parents and siblings (especially my little brother), but recently my anxiety has been worse than it has ever been.   


I also understand and value life more than I ever have, but due to extreme health anxiety (aka hypochondria) I haven't been able to feel comfortable since Mid January at this point. I know there is a subreddit specific to health anxiety, so I won't go into it too deep here, but I have essentially worried continuously that some kind of debilitating illness will either kill me or permanently change my life in a bad way.  


My anxiety is ruining my life. It's making me feel symptoms that probably aren't actually there, and it's ruining some of the relationships of those closest to me... even hurting my relationship with my girlfriend.  


Has anyone gotten through something similar to this? Does anyone have advice that could help? Please... share anything you think could be beneficial.  
As for what I'm doing besides asking reddit for help: I'm looking into Cognitive Behavioral Therapy and going to my doctor for a Health Anxiety or GAD diagnosis. I've been hesitant (anxious) to commit to either choice yet, but I'm hoping reddit could sway me.