I have no problem with people being gay, bi, or lez but...?

recently one of my close girl friends came out saying shes bi. Shes really butch for a girl and not the prettiest thing out there but my friends and I still loved her all the same. We had no problem with it. It was all find and dandy for a while but then i found myself more easily frusrated with her, annoyed being any where near her and always making rude commetns about her to myself. Long story short; I find it to be unbearable sometimes to be near her. Just seeing or hearing her sets me off! The worst part is that i have no idea why! I have no problem with a person's uality so why is that i find that i can't bear being around one of my best friends?! Is just because of her uality?