Should I restart year 12 in September?

I’m almost half way into year 12 and still don’t enjoy two of my A Level subjects and because of this I’m getting low grades. I got all 7s and 8s in my GCSEs with little revision in a mainstream school but my schools sixth form closed so I chose to go to a grammar school sixth form so have also lost confidence in my subjects. I am the only one of my friends who have moved there and have struggled to make friends (which is also making motivation difficult). I tried to switch subjects earlier in the year and my teachers convinced me not to. I am thinking about restarting A Levels at college in September to regain confidence and change subjects. Many of my friends go to the college so it would be better, however I am aware they will leave at the end of the school year. I’m unsure of what to do and would appreciate any advice.