Went over on my DEBIT card?

Okay so I made some purchases and it was a few days after all of them I thought I only had fifteen dollars in the band but I called Chase and it said I had 60 I was like wtf so I called it again and it said the same thing! I bought some records with my card on DEBIT for 28 dollars than went to Starbucks and bought two teas for I don't know 4 dollars now I call my bank and it says I have NEGATIVE eight dollars in the bank this math makes no sense to me. My dad said it might be because one of my purchases finaly deducted the money. I'm really scared I'm only 17 I can't afford to be paying hundreds if dollars I don't know how this could have happened I use debit for a reason please someone tell me what is going to happen to me. I bank with chase.