How do I stop it?? HELP!!!

My youngest Kj and I are constantly arguing. Is this because he is getting jealous that there is going to be another baby in our family and he will no longer get all the attention anymore? Its very frustrating. I don't understand his motives for behaving the way that he does. I mean when I was pregnant with him, Tj was always helpful and mindful of my needs. When Kj was born Tj was a great big helper and was excited to have a brother. Well, I was expecting that treatment this time around from Kj but I don't get it. He is the complete opposite.

I read week to week growth regarding my baby on the way as it also provides images of what baby looks like now with my boys. I mean it is starting to look human although Kj insist this baby is a zombie.LOL. I do it to try to get him as excited as we are about having another baby boy who is due June 29, 2011!! Kj seem to adapt to it and had already chosen a name for this baby. He is a huge BYU fan therefore he is naming his baby brother, Brigham Young!! No questions asked. I can assure you that is not going to be the name but I will let him think that for now!

Kj has been developing a temper these past few weeks. It got to the point where he would get mad at me and try and punch my stomach. His reasoning for doing that is because he knows the baby is controlling me and telling me to hit him or yell at him. I am so confused as to what I had done different with him that I didn't to with my oldest. Its starting to stress me out. I'm sure he will never attempt to do it again as he is afraid of what his dad will do to him if he ever attempts to hit me again but the point is what did I do to make him resent his baby brother??

One day he is kissing my stomach excited and anxiously awaiting for his baby brother to be born and the next he tells me he can't stand the zombie that lives inside me.. Uughh.. this kid is something else. I try to spend quality time with him and he still seems the same. He seems to grasp the concept of being a big boy now as he shows it through his actions and words however he acts different at the same time. How could the same son who asks me not to pick him up from school so that he can catch a ride with his friend(whom I have never met as they are only in pre-school), want to act out at the same time as if he is a baby still?? He is starting to worry me.

I know he is just a kid but some of the things he says to me are so random and offensive. Like he would tell me he loves me and the baby then the next minute he will tell me the baby is ugly and I should give it away. I mean really.. Are there other kids out there that act out like my youngest or is he just really random and I am all alone??LOL!.. I think we need to do something that will teach him to understand that he will be just as important to me when the baby is born.. but what??

I thought that I could buy him things he wanted and it will show him how much he meant to me, instead it back fired and aggravated me more to see how ungrateful he was.

I have tried numerous times to sit him down and talk to him one on one and he wouldn't even acknowledge me. Instead he would brush me off as if I wasn't even talking. Uughh...

I know my son loves both the baby on the way and myself, but I don't know why he is so angry.