SatoshiDice is gambling.  Pure and simple.  Like playing roulette.  The house is the only one who makes any money.  Learn your lesson and be glad it was only $600.

Also, what this person said:I don't know for a fact, but I would guess that gambling with rent money is one of those big warning indicators that you have a problem.

As an aside, I don't know why people go there.  Some guy on the bitcoin IRC channel was bemoaning how he lost $150 on some "97%" bet.  If I did the math right, he would have only won ~$7.  I can't understand why anyone would risk $150 even at that percentage to make a return of only $7.