Hello... I Have Been Having Some Stomach Problems... My Stomach

Hello...
I have been having some stomach problems... My stomach hurts really bad and when I mean stomach I mean my abdomin region from my about belly button down to the place waste gets released. I feel like I have to go but can't and when I do it's a little bit of diarrhea and water... It makes me feel like that entire area is getting smashed and hurts so bad. Idk what it could be or what to do...