When is there too much stress?

Being a teenager this days is stress full. I'm a 10th grader this year and I was so excited about not being "The Freshman". But with the new school year means homework again. With a 7 period day and the class time of 45-50 min. classes. When the teacher really gets into teaching the bell rings. Have you ever have a teacher who yells out the homework right when you walk out the door? That happens a lot to me. So, you finish the school day, ready to go home...wait after school activities. Now you have to go to practice or a game. You have to get your mind ready for that, but you can't forget the math assignment or the history paper due tomorrow. Sometimes you don't get home until 10 or 11 at night. You are so tired when you get home, that you don't even want to think about homework. For swimming we also have 2 morning practices a week and you have to be in the pool at 6 in the morning. But you can't forget about household chores either. Cleaning the room, doing dishes, or farm chores. Also there is athletes that have jobs to save money for college. That's my weekly struggle to push through. So when is there too much stress?