University works a little differently to college/ sixth form, its a lot less cliquey and people are normally more accepting to new friends, so don’t be put off talking to new people over worries they already have a group.
Loads of 1st years struggle with the move too, it can be a huge change to many, and there will be people who feel the same way as you.
Id suggest checking out your Uni’s resources, by that i mean check out societies but also check to see if your uni offers wellbeing, they will be able to give you some in person support which you may find comforting right now.
Really am wishing you the best!