Let me tell you that it is quite normal and perhaps the part of becoming a strong person. $15k though it is a decent amount (relative) but cheap for a life lesson. I know it still might be bothering you but now you know how to avoid and lock wins more efficiently so it is a good deal.
Thanks for sharing though it takes a great deal of courage to admit publicly your loss.
In fact, this is a huge loss for a loser in gambling, it should be unacceptable to allow such a loss, but people lose even big money, and not only in gambling. It all depends on the individual, someone can decide that this is acceptable for him, and someone just can not stop and despite all the losses continues to lose the last money. I saw a guy who went to play slot machines and lost a lot of money, but he walked in torn shoes. It seems that this is an addiction...