Chemistry A-level making me want to die

I picked chemistry A-level as a last resort as I fit the grade requirement for my school and no other subject has stood out to me. This has possibly been one of the greatest, if not the greatest, screw-up of my academic career.
For a start, I don't like my teacher; I find them to be abrasive and biased. Whoever told me that I'd "enjoy it at A-level due to it being different to GCSEs" is a liar. The same feeling of confusion and lack of explanation that I experienced during my GCSEs has followed me over into my A-levels, as it feels like I'm driving in a car with the brakes cut off. The content does not seem to be getting easier no matter how I revise -- and I've tried numerous different methods over three or so years of constant frustration at myself and the subject. As well as this, I'm more than certain that I'm unable to drop said subject and replace it for another as my GCSEs were relatively mediocre and all other choices seem boring and irrelevant to my ideal career path.
I'm kind of shouting into the void with this one, but if anyone has any advice or if they even relate to this at all then please let me know, as I'd be delighted to hear others' thoughts.