How can I make my mom understand?

ok well this year has been really stressfull for me so far. Im a junior in high school and im takin only one AP class but all the rest are honors. I stay up really late doing homework and the days that I finish early I usually just want to relax or hang out with my friends. My mom doesnt seem to understand how hard this year has been for me. When she sees me doing homework late at night she starts yelling at me saying that I always start my homework late, but the truth is that I get started as soon as I get home. On the weekends I usually go out with my friends and she was ok with it but lately she doesnt want to let me go and she starts giving me excuses for why I shouldnt go out. Now shes saying that if I keep asking her for permission that shes not going to let me go on vacation this winter, which I've had planned for almost a year. How can I make her realize that this year has been really stressfull on me and that I just want to have some fun with my friends on the weekends? its not like were doing anything bad!
and another thing, my friends always call me when they need help with their homework, or I call them. My mom thinks that were just talking about other stuff and doesnt beleive that were doing homework. Shes already said that she wants to take my cell phone away when I go out with her so it wont ring, but I really need it because me and my friends always hel p each other out wit our homework

Dear who it may concern,

If you can. Show her what you wrote. And I suggest you drop at least one honors class. cause that is way to much. You can always take it next year. or maybe a jr. collage. And also it may be better to just do your homework with your friends. But you need to make sure that your getting your how done when you are with them. Next, try not doing it with the T.V on or something distracting you. And sometimes, tell your teacher in advance that you might not get it dome cause of other classes and if they can help you finish that homework during lunch.
Hope everything works out. good luck.

If you are getting reat grades I do not see why it matters what you and your friends are doing on the weekends or that they call a lot out of respect for your mother though I would say turn the phone off or place it on silent when you are with her it would help her to see that you care about her to and not just your friends as well as that you can place some thing above them it seems like school and friends are all that is important to you an I being out side the picture could see your mother thinking that too. Try and do some schooling at lunch if possible or on weekends so that during the week you are done faster and in reguards to being stressed out just tell your Mother she might not SEE how stressed out you are and she can not read your mind you know.