My "friend" is flirting with the guy i like what should i do?

Okay this is a complicated story so ill start from the beginning. My friend, the guy i like, and i are on the high school swim team. Were all freshmen. Ok im gonna use abrieviations. MC= "friend" JO= the guy i like and BN= the guy i used to like. Ok so i liked BN at the beginning of the year and MC would always come to lunch braging about how BN voted for her for homecoming queen or was totally flirting with her. But he really didn't. It bothered me soooooooooooooo much because im one of those people that when they like someone they really like them(huge crush not one of those little ones. I've never had a real bf either which also bothers me. And no im not ugly! I have dirty blonde hair, hazel eyes, 5.5 or 5.6, so yeah. Anyways im totally over BN now so she stopped braging about it. And she always tells me how she has sooooo many make out sessions and everybody just loves her, one day she even got on the bus and told me that 5 guys told her she looked hot today. Now she knows i like JO and is starting to flirt with him too. She'll always try to draw attention to herself. She lies about how JO always smells her hair and flirts back with her. Okay thats the problem with MC, now heres another problem: Im wondering if MC lied to JO and told him that im obsessed with him or something because he's always acting weird around me. But he still flirts with me. Its confusing! Some days he'll come up to me in the hallway and bump me or play with my hair on the bus or come up behind me and pretend he's gonna push me in the pool! its so cute, Does he like me? This really confusing. Did MC tell JO a lie? Is MC trying to make me jealous? HELP!!!!!!!!!!