How to get your friend to stop liking you?

I've had quite a Lot of my guy friends asking me out :\ I'm a sophmore, and all my friends are basically guys and it's uncomfortable. When 2 asked me out, I BLUNTLY told them ""NO, I like you only as a friend. I'm sorry but pleaseeeee like someone else"" One guy, has been trying for months and he is 3 years older..(im 15)! T_T.. He kept trying for months, and said he was 'in love' with because Our 'souls'(NEVER tell a teenage girl that) were meant for each other..because SUPPOSELY we had a lot in common(only 3 things).. I tried being friends normally with him thinking he would out-grow it, I suppose. Never did.. He later on got obsessive over me, and thought I was starting to fall for him because I was being Nice treating him like all my other friends. But if I were mean to him he would become Literally Depressed.. The other guy, keeps telling me how he 'loves' me. BS. and I keep refusing, he finally stopped but i don't know what to do if he starts again. He keeps saying how in '10 years' he will ask me out again..?! And no i'm not trolling.. lol xD i've only dated one guy my whole life, which was earlier this year. So I don't really know how to handle these type of situations.. I dont know if im doing anything wrong?? Just don't want to be extremly rude, but it's really out of control.. Any answers would be great! Sorry if it's too long.