I am so depressed because I am too sensitive!!!?

Please help.... Today I have a really bad day.... my class have to go to kayaking and the instructors are super fierce.... When I went to kayak, i feel like I am in the army. I tends to be a little bit slow, cant get it straight to the point and have difficulty understanding and the instructors just hurt me both physically(he pull me up from the water rapidly and my butt hit a hard metal) and mentally by scolding me.... I really tried my best and it is my first time kayaking... My friends complain about it too and at the end of the kayaking, I rethink about it and suddenly I feel like crying and I cant control it, it just get better of me and I cried because it was so tiring and scary. My friends questioned me and they tell to my teacher and while I complained to the teacher, I dont know why but my tears were streaming down non-stop, I cant control it and I tends to be afraid of teachers too. I think I have this social anxiety disorder, I am afraid of teachers, afraid of what other people will think of me, I dont dare to speak out. My mum tolds me I am quiet since I was baby... When I was a baby, I dont talk nor cry most of the time, I just stare and stare.... I think I am born being a quiet person... I so tired of being sensitive!