Social life does revolve around alcohol, at uni and outside of it. If you don't drink at all, you will find it difficult because alcohol is how people socialise and get to know each other.
There will be others who don't drink though so talk to as many people as possible and try to find them. What do you do to socialise without alcohol atm? Whatever you do now do socialise, you will be able to find others in London who do the same.