Have you check yourself to the doctor?
I once had a massive stomach cramp for 4 days. Then I couldn't stand it anymore, I went to the doctor. Seems my intestines were infected because I drank a bad yoghurt >< The doctor said, "You survived for the past 4 four days in this pain?" The doctor was quite amazed with that XD

So, yeah. You should check to the doctor. Probably you ate something that's not very good.

Take care *hugs*