My friends are mean or im being jealous or what?

It just used to be me and my best friend for years, but we became best friends with two other girls. We've been upset at this one girl for a while and shes telling everyone that were ugly and bitches. My friends are gorgeous and they always tell each other that...but never me. If i ask how bad my hair looks, they grumble and look away. If they ask each other that, they'll be like "omg it looks sooooo cute!". then we got pictures back from school and my one friend was complaining "omg i feel so bad im so ugly" but then she looks at mine (which i didnt think was all that bad except for my hair) and she says "oh now i dont feel so bad" and the two of my friends laugh...i got really upset at them and then they ditch me at the rest stop and dont wonder where im at and ignore me the rest of the way back home...i ignored them, upset, and even the girl sitting next to me left her seat...im not smelly or anything and i know im not a model (im far from it) but im not like REALLY ugly, tho i guess i only think that because my sis and other people tell me im pretty. im still mad at my friends so do you think im being a ***** or are they? I want friends who tell me im pretty even if im not...or is that just not how things work?