Open Question: i am 17 years old......i have been takin out cum from 15.....3 or 4 times a week...sometimes 2 times a week...?

but the problem is after i take it out i feel dizzy,sleepy for the rest of the day.even ........i get a headache sometimes......i am a gud student.......bt i need to know if dis is a disease or not becoz my friends say dat they do it everyday but nothin happens to them.....nowadays i take out only once a week......should i stop it totally?........has it got many side effects??is it dangerous??is it harmful for the memory or my nervous system??