21 is still very young,  dude. You've got more than enough time to switch this around and it sounds as if you're getting ready.  Weight loss seems to be the biggest issue and also the smallest. If you begin socialising more and  become happier with yourself , your body may change anyway due to new habits. There are a lot of people chubbier than you loving their lives  .    Social awkwardness isnt the end of the world. If that girl likes you others will too. Trouble is when people don't know how unhappy someone is wihj themselves they wont understand why you stand them up/dont talk to them etc. They might blame themselves. People dont know these things about us only we do.   I repeat my first sentence. If you need some medical help for your anxiety , get it. If you want so socialise more, make the effort even just once will help you breed healthier mentality.     Can you tell us anything you like about yourself and your life?