I completed my university education in one go; however, I was in the same social predicament that you find yourself, but I had my goals and making friends wasn’t one, so I really wasn’t bothered about being lonely at university.
In your case, I suppose you can make friends by joining social clubs and participating in university programs, if you really wish to make friends. Ultimately, you can’t force friendships, but I’ve found that if people find you interesting enough, they’ll want to be around you - go figure. Lol.