I went through a similar situation with my child. What happens is that you will withdraw, and the institution will process your account. There is a formula that the institution uses to figure out how much if any you are due as a refund, and if so how much will be paid to you directly (if you paid any of the tuition and fees out of pocket in addition to the loans). The refund (if any) will be paid to the lender, and the lender will be notified that you have withdrawn. You will still owe any remaining balance to the lender. It would be beneficial if you spoke to the financial aid office at your school so that they can explain to you the process in detail. You may also want to call the lender to see when payments toward the loan need to begin if you do withdraw.
I'm sorry. There is an institutional formula that the school will use to determine how much of your tuition will be refunded to you. This is based on your attendance. The school will generally keep whatever loan proceeds they have to cover your tuition balance, and then pay the lender if there is anything left. So no, you should not owe the school, but you should check with the school's billing office and request a final bill or final account statement to make sure that there are no errors.
Presumably, if there is no refund past the 1/2 way point of the term, and the school keeps the $2500 for tuition, and you have kept the $500, you will still owe the lender $3000.
You will need to speak to the lender and possibly the school financial aid office to determine whether or not you are still eligible for any predetermined aid next semester.
I am sorry that I can't be more specific, but this is generally the way that it works with universities and fin. aid lenders, but different schools have different policies regarding tuition and loans.
Please get the names of contacts at your school and the lender's office, and request statements in writing to protect yourself.