Omg i saw my bff and i liked it?

my best freind (girl) sleep over to my house an i see her when she changes clothes. i only see her top part but omg i got a felling in my tummy!!! i think about it non stopping. now im scared to her coz i have a bf and i dont wanna be lesbien. am i weird? i got no place to ask this so sorry if it stupid!!!