11 year old boys....make me want to shoot myself!

I am not sure what the hell the problem is, but I have had ENOUGH! It's like Dawson woke up on October 13, 2010, his voice sounded a little different, and his attitude really went to shit! The attitude was already going to shit before his birthday, but it's like over night, maybe he got a peach fuzz down south and decided he was a man or something. He went from an all the time all A student to bringing home 50 somethings on progress reports. Acting out at school, getting conduct marks DAILY, doing his homework at home, yet not turning it in when he gets to school. Bowing up at adults. Mostly me, but he has done it to Bob, and he talks to his dad like shit too. The difference there is that I do not let him get away with talking to me like I am an idiot. I don't spank him very often, but I just did today. With Keigan's belt that has metal eyelets. Do I feel bad? NO. Should I? Probably, but I have had enough. I am to the point of wanting to send him to off to some summer camp for troubled boys. Right about now I have come to the conclusion that 11 year old boys are assholes and they SUCK! Call me a bad parent, call me whatever you want, I do not care. His attitude is 10 times worse when he comes back from his dads house, and just as I get him acting a little better, it is time to go back over there again. Of course his dad doesn't want to get on to him when he does wrong because he only has them every other weekend during the school year, and every other week in the summer. He does get onto him sometimes, but not always when he needs it. If anybody has any ideas that may help, please, TELL ME! Is there an end in sight?