I have 3 boys who all fight like cats and dogs too.
I know it's hard. Has your son ever been to school? I have a friend who sent her son to kindergarten, then pulled him out to homeschool him. When he was having bad behavior she would say "I'm gonna have to send you back to school". And he would cry and BEG her not to.
School is not so fun. Homeschooling is! Maybe your son doesn't know that if he hasn't attended a traditional school.
Have you tried taking things away? If his behavior is not good during school, then he loses things he loves. He must have a "teachable spirit". If not, he will lose tv, video games, going outside, playing with friends, toys, anything and everything he enjoys..........until he has the right attitude. I used to tell my older boys, "I'm going to put
everything in the attic........you will have
nothing left!" and just the threat was enough.
Let the little things go. Allow him to work independently as much as possible. I know it's hard to be his mom AND his teacher.
Here are some articles on homeschool burnout. -
http://homeschooling.about.com/od/burno ... urnout.htm