I'm sorry this is happening. I can understand that it is not easy.
I agree with the others - Why will they get mad if you kindly ask them to turn the TV down? They have to understand that their daughter needs to sleep and get up the next morning to function.
For the meantime, maybe invest in noise cancelling headphones. There's some decent ones for $20-$30 at Target or Walmart. Shut your door and use headphones, that's the best I can think of.
Can you go to bed before they start watching late night TV? If they're watching TV at 3am, maybe try heading to bed earlier to beat them, by falling asleep. For insomnia, try shutting off all electronics an hour before you want to fall asleep. Grab a book, draw, write in a notebook, or sit back and listen to calming music in that hour to help you calm. That way you'll be up earlier in the morning so they won't say anything about that. I guess it's all about finding a way to work around their noise for now until you move out some day.
I feel your frustration because I've been in a similar situation. There's a lot of noise during the day and it's hard to concentrate on homework. I got some headphones and turn my music up and it helps me. I also try to do my homework before anyone gets home. It was hard at first but I got used to it and kind of happy to get my work out of the way earlier
All the best!