I’m almost 17 and I’m in the 11th grade.
I grew up in the USA, but I moved away from there soon before my 14th birthday. I'm really homesick, but that's the smallest problem, I’ve moved twice to 2 different countries due to family problems and this didn't ‘t have a good effect at all on my education. I used to be an A student back the states, but the moving effected everything so badly that I’m actually afraid of failing and not being able to graduate. I live in Hungary at the moment with my mom and 3 siblings and we want to move back, but if we did, we wouldn’t have a place to stay nor would my mom have a job. What should I do? I really want to become a doctor, but unfortunately I’m afraid that if I stay here, I won’t be able to. I try my best at school, but it’s never enough. The teaching system as well as the language is totally different here and it’s something I just can’t get used to. The only positive thing about this entire situation is that I managed to learn a few languages moving here and there. I’m learning my fourth language at the moment.

Have you considered attenting an American school? There is one in Budapest.
http://www.aisb.hu/

You could ask your teachers for any way to help boost up your grades; if they see that you are making an effort, you may be able to buy some points with that. (I suffer from depression and my teachers understand how tough some things could be, therefor they are slightly easier grading my work).

If that doesn't work, start with either trying to get extra credit assignments or asking a student to help you. If there is a friendly; smart student that you think would be willing help you, there is no harm in asking them for help.

YouTube also has A LOT of tutorials, so maybe you could find some tutorials on some subjects. Most school subjects stay the same no matter what language they are taught; math and geography are share the same rules as in English, it's just understanding the other language that could be a little bit difficult.