What Causes Abdominal Pain And Diarrhea?

I used the bathroom twice yesterday, and each time it felt like i had diarreah, but the pain was a little different, so that is why I thought something was wrong. Anyway, I felt like it was just diarreah, which i get time to time, once every couple of months, but when i wiped myself, i noticed that it was clearish/watery looking, when i got up to flush the toilet, the toilet was not very dark. There was some fecal matter in the toilet, but mostly the clear/watery stuff. During this experience, I felt extreme pain in my abdominal region, and lower back pains. I also felt like I had to throw up during it. I feel kind of weak this morning, and i'm not very hungry, but I am afraid to eat, I don't know what to do. I'm kind of nervouse because I have an audition in 2 weeks and I don't know if this "temporary" sickness is going to effect it.