How do you really get over someone?

okay so i saw this guy a few days ago at school and hes in a diffrent homeroom with a diffrent lunch period. i barely kno him but i kno his name. all my friends tell me that i need to get over him because everyone says hes either ugly or a womanizer (even tho they really dont kno what it is). the friend thats calling him a womanizer says its someone who's an to girls. but i really like him and i don't kno what to do! should i like talk to him? or like get a friend to help me talk to him? i'm kinda shy at first but when i kno someone i can be really loud and kinda obnoxious. and im not the prettiest girl ever. even tho people tell me i am. PLEASE HELP!!!! :(