What to do if you get stuck with a subject

I have this big problem since the 11th grade started. I'm not doing well at math, my grades are pretty low and I'm worried about it.

I arrive from school approximately at 3:30 or 4:00 P.M. I feel constantly exhausted and my body hurts at any movement. I feel like I haven't slept in weeks, and my parents just don't leave me alone making me feel even more pressure on me.

Trigonometry is killing me and the teacher doesn't pay attention to me whenever I ask him a question. I feel mostly like time after school is not enough form me to cover all the subjects including resolving my math issues.

I have abandoned all the atcivities and hobbies I enjoyed to do, because of that and I feel like I'm entering into an state of depression.

I would like to know a way to manage my time better or any study tips to improve my grades before it gets too late.