Sounds like you're carrying a lot. So, instead of carrying so many things, try and cut down on things you don't need. Maybe use more than one binder so that you only need to bring home what you need and not much more; Think about how much you DON'T need in that huge binder for one night's work. If you have only math homework, why bring home math, science, AND social studies?

Use a backpack with two shoulder straps so that the weight is evenly distributed throughout your back. Try and carry as many things as possible in your backpack. Cut down on the things you bring. Instead of bringing sneakers in your bag, try wearing one pair the whole day. Good luck.