Please dont lose hope firstly, hope is everything and remember how lucky you are to be where you are right now, many would ever get that chance, but i understand how lonely it can get.
Drinking culture is an interesting one, and i was discussing this today with some colleagues. Its embedded in the brits culture especially and difficult if you dont join in for sure because filtering out your demons is not so easy if you dont drink, however i can guarantee you feel better health wise to be honest, and probably mentally better than your class mates.
It sounds like you are trying to branch out which is great, and indeed it must be draining when you dont find many people to link up with in those groups either, i understand and have been there in some respects myself. What you need to do is love yourself a bit more and not see yourself as an outsider. Believe it or not but many people who you think are popular and embedded in a close freinds group are the most insecure people you could meet, they just throw everything at saying the right things to impress others, becuase they prioritise that over their happiness - its a thing.
Try not trying .... relax, smile, find in the crowd of idiots a few calm people, old souls, and get to know them. Listen to them dont moan, and make conversation about nice topics.
Its hard I know and different according to wehter your male or female, i think your female ?
PM any time ok 🙂 Neo