First of all, I want to commend you on making it to where you did given your history in school, study habits, and other issues. Keep up the hard work!
I have a FB friend, someone I went to HS with, but didn't really know all that well. Now and then he posts pictures from interesting places he travels to for work. The last time it was from Europe. My first thought is "what did I do wrong to be in a dull nursing job and not travelling the world?" Then when I think about it more, I come to a few realizations: first, these exciting things are probably 1% of his life. He, like most people, don't post about he 99% that is mundane (or worse!). Also, some of his life my look glamorous, yet I know he has made, and continues to make, many sacrifices to be on the business trip overseas. He may very well have FOMO when he hears about FB friends going to their kids sporting events, having a guys or girls night out, or just spending time with friends or loved ones. FB and social media in general give you a very skewed view on the lives of one's "friends." The post what they want to post, and you can't assume that their lives are better than yours.
Having said all that, life without social media is possible. Yes, I go to FB now and then, but most of my interactions with family and friends are not through social media. I know people who have lots of friends and a very active social lives, and they don't even have FB accounts. Call people, text them, send letters. You are in school now--here's a chance to meet new friends. You will soon have a new job. Another great chance to meet more people. FB is no the be all, end all of social interactions--far from it.
Finally, I'm not going even flirt with giving medical advice on the issue of happy pills, but I think it might be useful to find a professional to talk to about your anxieties. Just my opinion, but I think this could be helpfuleven if you do not want to be on medication.