When im scared i shat myself...?

I really dont know why but like i always have to **** really bad whenever i get really really nervous or excited. like when i did cheerleading competition a while back and right before the girls and i got on stage we would all of course be really excited and nervous but i would always have to **** so bad that right when we would get off stage i would run to the backstage bathrooms and **** so much. But now its getting worse. what should i do? and dont tell me to wear dippers -_- im being serious here