When you "go away to school", you are still a resident of your former state until you take concrete steps to change your domicile. Being away at school is only a temporary absence from you permanent home state. This is particularly true, if your parents claimed you as a dependent.
If you filed tax returns, in the school location state (or any other state, e.g. summer jobs), and paid tax, your former home state will allow a credit, or partial credit, for the tax paid to those other states. The solution to your problem may be to simply file back tax returns for your former home state.
