I ate some raw beef by accident, is this bad?

I made myself a hamburger, it was only cooking on the outside. Which it was starting to become burnt on the outside, so I took it off the grill. Well, at first the edges tasted fine, but I kept eating it. When I got to the middle of the burger it started to taste odd, but still kept eating it. I ate like 3/4 of the burger, then I was like this doesn't taste right. I looked down and saw it was still red on the inside, and I was like man I didn't cook it all the way. Well, Im a person that never wastes, so I ate it all. Now my stomach is aching a little, I don't know if this is real, or its all in my head. But, I did drink 2 bottles of water after I ate the burger. I don't know if that caused the ache. Also, it was beef that I bought 2 days ago from Marsh. It came in a Styrofoam container, with a elastic wrap around it. I opened the elastic wrap yesterday, and left the beef in the fridge. The beef was uncovered too.