School loan repayments

How is it, that one can get an education loan, for a tic-tac over 5% APR, $21k, pay on it for 6 year @ $200+/mo., and still owe over sixteen grand, and still have 113 payments remaining? I mean, really. WTF?

Let's do some quick math... 6yr X 12mo = 72 72 x 200 = 14,400. 21000 - 14,400 = 5700 + Int. so somewhere in there, is a magical 11,000 in interest?

I'm no loan officer, or calculator for that matter, but I smell some butt-sex and I'm the 'catcher' in this financial "relationship"...