well done for trying to help, i don't think she's doing ti for attention have there been any recent incidents in her life that would make her depressed?

what about going to her house one night or ring her up and just talk about your day and ask about hers you know just casual talking and see if she's eaten if she's had a bad day etc ect then that would give you a better idea of whats going on, you could try talking to her saying your worried but that may not work if she's already angry with you. You could try going out places with her then get the other people your with to say good things about her e.g. "hey your looking good tonight!" or " i love the top your wearing" etc just things that will make her more confident and feel good about herself