How did I lose so much money on adwords, what can I do?

I set up auto payment with google adwords, to my credit card, I set the daily budget at $15000, never thinking it would get even close, and I set the bid for the keyword "sex" at $4.00 per click, globally, I went to the store to buy groceries, and when I got home my credit card was nearly maxed out, I am 15k in debt, and I got a whole bunch of hits on a site that was just a test on my part, what can I do?