Should I study anatomy & physiology in high school?

No. It could mess up your GPA if its a hard class just take it in college. Btw a psychiatrist is a really great career choice.

You need A&P, but it's troubling that you've had problems with this teacher. If he/she is capable of torpedoing your GPA, it's safe to put it off. However, when you do take it in college, you will need a 4.0 in it. Do what you have to do to make it work.

Spanish is ok from a practical standpoint. But if you're going to do anything in medicine, you will be getting a lot of Latin terms. In the old days, Catholics had a decent grasp of Latin. If you don't, you may want to fix that.

Good luck.

This isn't lol kiddo. No. You don't have the academic ability to handle this class and it will probably tank your GPA and you'll blame the teacher instead of taking responsibility for you own learning. IF and it is a big IF, you are on the pr-med track you'll have to take A&PI and A&PII in college anyway.

You're SCARED?? Of what? Take the classes that you want to take, dude. You shouldn't have to ask random strangers on the internet for opinions.