Repeating year 12?

I went to a very diverse secondary school, but the college I go to now is the opposite, which is why I didn't really make a lot of new friends in year 12 (apart from my school friends who attend the same college). I still have another year, so I know that I could try and socialise a bit more to have a better experience, but I'm considering if I should re-do the year, at a different (more diverse) place. This is also because I'm scared that if I don't enjoy university (as a lot of people say they made better friends in school), at least I would've enjoyed A levels. In terms of A levels, I'm a bit behind, but not so much that I won't be able to catch up. However, a problem with repeating the year would be that I won't really be able to take a gap year. If I don't get accepted into university when I apply this year, at least I can take a gap year and apply again, however, if I repeat, it'll be 2 years instead of 1.

Does anyone have any advice.

Stick through year 13

Focus on your studies first. Im assuming your in year 13. The year will go by fast.
November, January, March mocks, May/June real exams
You have exams every 2 months since September
Your friendships will only last till the end of year 13 (mostly) before everyone goes to different places with uni
You are not lonely - you have some friends