Stop stressing! it'll be fine!
*When i started uni i didnt drink, and was kinda terrified of going out, i went out 2/3 times in freshers week with my housemates and other people, and it was decent! I had one or two drinks, but mainly just enjoyed being with new people dancing to some good music!
Seriously, I wasn't a fan of freshers, but I would definitely say to try and go out (but you dont have to drink).
One of my flatmates didnt go out, and has only been out clubbing once at uni, and hasn't really made many good friends. She has friends on the course to sit with and stuff but because she hasn't joined in ever going out, people aren't really sure when to invite her and stuff, so she misses out on the bonding that occurs outside of uni itself.
Dont stress about freshers though, I didnt really enjoy the nights out that much (although i enjoyed them at the time), I found i made friends on my course and enjoyed nights out with them a lot more tbh.