Personally, I hope this isn't spam. Sure, I find the fact that a person can get a rush out of seeing dogs killed sickening, but at the same time, if the OP feels any remorse at all, then there's hope. I don't think a true killer with only the desire to kill in their heart feels remorse afterwords.
My suggestions would be to seek professional help (hell, if you're 18 and a tattoo artist you must be pretty good at what you do, so I wouldn't believe money is an issue) and go watch a dog sport other then fighting. Watch a dog run a perfect run in agility, or a schutzhund dog make its way to the sixth blind, or a dock dog beat a personal record. That's a rush. You can go out and see dogs in the world succeed with out killing the opposition, and that's a rush, because those dogs you've come to see as cute and funny and cuddly now, are still alive in the end.
And personally, I wouldn't introduce myself as a dog fighter. The world doesn't need to know what you did, especially now while you still miss the rush of it.
You say you were born into it? What about the kid who was born into poverty but made it to school and made a life for himself? Or the girl who was born into an abusive family but grew up, and had her own children and would never dream of laying a hand on them? Only YOU control you. You're an adult. You can change you.
Time to stop missing the rush and realize that you don't need it. If people can beat the rush of drugs, you can beat the rush of watching innocent dogs rip each other to shreds.