Excess Perspiration Help?

So this topic is a bit embarring for me, but I'm so tired of it. So this is about my under arms. In school, I sweat so much. It's so horrible. I wore a sweatshirt today and it even went through that. It was such a long sweat stain! This only happens in school, not at home, so I don't think I have any disorder of it. I've tried Secret Clinical Stregth, Dove Antipersirant, Mitchum, Certain Dri AM. Nothing works. Please tell me what is causing this and any suggestions.