Sweating Only at School or Some Special Event

It's weird, i only sweat at school and some kind of activity that has to do with other people, but when im at home or something, i dont sweat, unless i get a phone call from one of my friends, and then i start sweating, its horrible!

I think that not even my mom knows because she has never seen me sweat like that, anyway, i cannot wear normal t shirts because if i do i start sweating, and if i notice that, i sweat even more, then, if i wear a sweater or something, i dont sweat as much.......?