Anal leakage ??

The last few days I’ve been getting these insanely painful stomach cramps and I’m having on and off diarrhea, but last night I got up to go pee, and I went with all the lights off because I didn’t want to burn my eyes, and I noticed the back of my underwear seemed kinda wet, I figured it was sweat because my room was really hot when I woke up. And now today I wake up and go to the bathroom and noticed the back of my under has a spot that’s tinted like a yellow brown color. Is this normal or something to worry about ?