What am I to think about girls at my college if they are unkind to me but nice to each other and the lecturers?

I am a very shy girl. I wouldn't hurt anyone. I have this lecturer and she likes all the girls in the cl and I know you will say that my personal issues with them have nothing to do with how she gets along with them but surely there is more to morality than that? It feels like people are stepping on my head and leaving me for dead and in a year I probably will be. I don't think I should have been born. Why does my lecturer like girls that laugh at me when I have to present or I say hello to one girl in particular she rolls her eyes at me, another girl embarrased me in front of the group..all of these things but my lecturer quite likes them I guess as they are quite outgoing and know what to do socially..does she sound like a nice person?