Yes it's a problem. State guidelines differ from state to state but you should not be working that many hours. State penalties can be very heavy for the employer. In Ky you can't work more than 20 hrs a week while school is in. And you can't work past a certain time. And I believe it is 10,000 per offense. To be sure in your state look on the poster in the employee break area it should have the info on it. It is the poster that says equal opportunity employment. If your employer doesn't have that up , it is another broken law. child labor laws are different than adult labor laws. anyone still of an age where they can be in high school falls in this category. if your in Ky and you are under the age of 18 and you quit school you can still only work 20 hrs per week.
Most laws regarding underage work are regulated by the state. I can only speak for Alaska and by law you can not work the kind of hours you are talking about at your age. Here you would also have to have a signed release from the state for you to be able to work at all. This must be signed by your parents and faxed to the state prior to your employment.