What should i do?? everybodys tellin me sometin different!!?

This guy liked me and he asked me to prom but i thought he was kidding so i just smiled and said egh! nah but while at prom he danced with this GEORGIOUS blonde girl from a different school. then the next night he hung out with me and since i missed prom he put on the song his parents fellin in love with and asked me to slow dance in a parking lot. But as soon as i got to school he kept talking about that prom girl i dont know what to do! i feel like it didnt mean anything at all. my parents say hes playing me and my friends are saying it was just one night and if it was then how come he keeps talking about her? i feel like crap everytime he mentions her name cause lord knows i cant compete with her what should i do?