Help? Advice? Relationship problem...

Just a little background...my fiance and I have been together for a little over 4 years and we have one child already.

I just found out about a week ago that I am pregnant. I will be 5 weeks along on Thursday. My fiance and I have been trying for the last 2 or 3 months.. I thought he would be as happy and excited as I was when I got my positive pregnancy test. Unfortunately, he basically called me a liar and said I needed to retest. So the next day, I went out and bought a digital that said I was PREGNANT. Then he believed me but showed no excitement. He got upset with me when I told my mom and sister and upset again when I wanted to tell his mom and sister. This all seemed just weird to me.

Our first was an oopsie and I didn't feel like I got to celebrate being pregnant and all that. I was excited to get to be excited about this pregnancy and now he's acting like he doesn't want it. Just to clarify, he was aware and in complete agreement to try for another! He was even excited about it... Until I got that BFP...

Tonight in the car, I was having a hot flash and cracked my window. So he turned the heat on full blast. And we argued about this stupid little thing! "I'm hot" and "I'm cold" back and forth! Then, he says to me, "Why did I ever get you pregnant again?" And I said that that had nothing to do with this fight. And he said, "Yes it does, because I don't even want to be with you anymore!" And he's dead serious...

WOW!!! What in the hell!? I don't understand how things went from fighting over the temp in the car to he actually doesn't want to be with me anymore! I don't know what has been with him lately, but it has all felt like it's been building to this! I don't even know if I want to be with him now with the way he's been treating me. I don't even know what to do anymore!! :(