I have OCD please help?

ok, so i wash my hands like 50 times a day with different kinds of soap like bar soap and detergent and it's so a waste of time, i mean i cannot stop it even though i know my hands is like very very clean and i get very anxious a lot as in a lot. I check doorknobs like 2 times to be sure it''s locked and i don't like odd numbers. I'm quite depressed because it is like i'm the only one who have it in school. My elder sister calls me crazy too and one more thing the light switches i like to on and off it like 8 times i don't know what to do. My mother does not even know i have one. Is there like a medicine or anything that i can take to lessen the worries.