Is it normal to be 'used' all the time?

I have another 10 months to go before college ends,and boy!,that's a really long time to me.I'm doing my A-levels currenly,and i'm staying away from home,as college is in the city.I have a group of 6 girl pals,and they are really nice people.In the group,i'm the only one who is from oustation..things between us went on smoothly for a while..not sure why,but things drifted apart.5 of them are of the same race,and me the different one.They speak their mother tongue while having conversations,and i'm the only one left out.normally,they would go out to lunch/hang out after college,and I usually don't follow as I'm not really into this whole hanging out thin.Plus,i normally take a nap in the afternoon,so that i can study at night.I guess,they got sick of asking me out,as my answer is always NO..recently, at all the birthday celebrations and hanging out events,i have not been called,even when i was actually willing to come along..It hurts me,actually.I am their source provider for studies,and i feel used,because they totally ignore me in terms of conversations,but will only talk to me when i have some infos for them..they are so rich,and still they owe me money.and i'm not the type of person to ask people back for money.we had a lab report to do recently,and one of my friends told me to write a small part of it,and give it back to her.when i did,she was angry at why i didnt type and print it.she never did ask me to print it,so i dont know whats the problem.and i think she badmouthed me on twitter.i sent her a text justnow,saying that it was a miscom and i was sorry.no reply from her.i feel like crying all the time when i think about this.what should i do?