Clear Anal leakage

Hey, I'm 15 years old, 5'5'' and i weigh 145lbs. Im fit and active. Whenever i sit up for around 30 minutes, i feel a warm moist feeling in my pants. Its been happening for about two weeks. I took stool samples and nothing came up. I cant go to school and i dont know what to do. I thought it was sweat but its too warm, and too moist. When i go to check my pants there is no fecal residue that i can see. The doctor also check for blood in my stool and there wasnt.

[Ratnakar ., MD]

Hi,
Did the doctor do a digital rectal examination?
Did he examine the perianal region?
If so what was the finding?

[Fuzzz]

It sounds like mucus.  Usually mucus is produced because inflammation.  
I have read that some people get complete relief of colitis by going on a gluten-free diet, even though they have colitis, which is supposed to be different from celiac disease.