Something Happened to Me Last Nite, I Need Your Suggestions

I had a horrible evening last nite, as this has never happened to me before, never! I'll tell you what happened and I am open to hearing anything that it could be and what type of doctor I should see, if any. Thanks a lot!
Last nite, my mother and dawson and I went shopping and went to mcdonald's. We both had the #3 which is a quarter pounder w/cheese and a french fry. I also had 1/2 an apple pie. Now, on the way home, I said to my mom "ugggh, the mcd"s is starting to get to me" as it sometimes but not always does. I started feeling pain. I went in and went to the bathroom. Nothing. All of a sudden I started feeling horrible, horrible pain radiating from my uterus all the way around to my a-hole but I could not push hard enough to push it out. The pain was so bad, I actuall had to breathe through them (like I was in labor) and I was practically screaming like I was in labor. After 1/2 hour of this, I was still in severe pain, couldn't walk standing up. Made it to the pot again thinking it was finally coming and again, severe pain. I was hanging onto the window sill on one side of me and the cupboard on the other side of me breathing through this pain and/or contractions. It was horrible. I called my mom and she said to take some mylanta, which I did. Then I finally "poopy" a little. I was a little better then, at least tolerable to take care of my son. I was going to call an ambulance, that's how bad it was. I know it might be irritable bowel syndrom, but why would my uterus (front side) contact so horribly? Any suggestions please !!! Lol what else could it be? Do you think I should go see a doctor? Maybe it was just mcdonald's, I don't know.