Since when is not eating meat a hindrance?
Drinking could be an issue because it is a social thing but, not much of an issue. Most people go to the bar, you can still go (am I not correct in assuming) and simply just get a juice, coke or water.
I only drink socially (when out with mates) and will VERY rarely drink by myself because I view drinking as more of a social event and less of something you do yourself unless your dying for a beer, cider etc... so, it is a good reason to meet up but isn't a necessity to do so, nor take part in it.
Just join a society or make friends by socialising at the beginning of the year.
Most people at uni will talk and want to get to know each other at the beginning of the year, best thing to do is just go with it. I actually ended up going to uni late (missed like 3 days because I got my start date wrong...) and ended up talking to someone who also started late, then also ended up meeting some more mates, made friends with his mates etc...
Socialising and making friends isn't hard unless you are one of those socially awkward people.