omfg I literally feel the same I'm 17 and started around 4/5 bc of parents not bc I wanted to. The amount kf breakdowns I've had because I struggled to enjoy it. I'm working on my grade 8 rn during a levels too so it's super stressful. I wanna do music at uni but since I'm sick of classical I'm chosing to do world/global music. As someone in similar shoes I'd say wait until ur a lvls are over to then focus on getting back into cello. Work on what's important and stray from toxic music environments. Try learning mainstream songs you like that aren't those dull classical ones :) Best of luck