Just checking....

I just stood up to go get my youngest up from her nap and I had such a bad pain in my lower abdomen and crotch I thought I was going to cry...I had to stop what I was doing for a minute. It felt like tons of pressure and like a balloon was about to pop. The only way to make it stop was to sit down and I'm going to have to get up again because now I have to poo. I'm sure this is completely normal, but what could it be? Could it mean I may be dilating or something? Sorry if this is a stupid question...