My advice is just don't pretend to be something you're not (what's the point in friends if you can't be yourself around them?). Don't be afraid or worried to be by yourself, it happens to a lot of students at first.
If you don't drink for whatever reasons it is going to be more difficult for you initially if you want to make 'friends', but as others mentioned MOST of the 'friendships' made on these freshers nights out are superficial and don't form any lasting bond (i'd actually say the same applies to the none drinking/sober fresher nights which are often arranged).
People on them nights out might even regret it later since you have this weird relationship with people you've met from those nights out where people feel so desperate to fit in and you can tell it's a 'friendship' formed out of desperation and fear not to be alone rather than any real connection, to me it only shows a weakness of character. The benefit you also have with not drinking is you don't end up acting like an idiot by accident and regretting it for the entire year.
And once freshers calms down, it's fine, you meet people on your course etc and there's no pressure it forms naturally.
So don't worry about it.