ASS-P - Eating as healthily as you can, getting exercise, doing things that make you feel good... they all help a little.
But as for making friends, I don't know, I'm terrible at it (apart from the fact that social conversation exhausts me/bores the pants off me/annoys me excessively); I could say that you might meet people if you go to the gym (sorry, an expense I know, just using it as an example), or join a club, but meeting people, and getting on with them/relating to them, are two different things. Joining a club or something could just be seen as a way to occupy your mind with something different for a while, even if you don't really connect with anyone.
Variety in life helps... force yourself to do different things... make time for them... They don't have to cost anything. I've been where you are.
And, no, don't get drunk too much
(does help sometimes with the whole social thing though)
Sorry if this is a bit lecturey, I probably do that too much.
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AS/ADHD/OCD software bundle installed.