Considering dropping out of sixth form...

Hi! I'm really conflicted right now about whether or not to stay in sixth form. I just turned 18 and I'm currently retaking year 12 because I had a lot of mental/physical health problems last year. It's been almost two years and I'm still struggling to get a diagnosis from my doctors and because nobody knows what's causing my symptoms my attendance at sixth form is really poor.

My school aren't really offering any support and keep telling me that I'm going to be unsuccessful in the future and I really hate the whole environment at my sixth form. Even with my attendance/health problems my grades never dropped and I'm still predicted A*s but my teachers are just really not supportive.

It's really hard retaking year 12 because I feel like I have no friends in my new year group, my teachers keep telling me I'm destined to fail because of my attendance and I'm really conflicted about whether to even stay in sixth form at this point.

I could really use some advice. Thank you!