Back again but dissapointed....

Well, after 2 weeks of not running, I finally got back out there today - Only to be sent home early with a terrible side ache. I had only been running for about 5 mintues when I started feeling an ache in my side. I've had them before but this was unlike any other I have had. I decided to walk for a few minutes which made it feel better, but when I started running agian it hurt so bad that I almost doubled over in pain. So I decided to walk a few more mintues, my side felt better but the same happened again once i started running. It was like when i started running someone was stabbing my side with a dull knife. So unfortunately I had to just walk home. Has anyone else had this happen? I don't know if I drank too much water before or what. Needless to say, I was very dissapointed. I was really looking forward to getting a run in. Oh well, we'll try again Wednesday. Only 26 days until my next 5k (May 12).