How could she do this to me?

you seem to have some self confidence issues. This may hurt, but just all in once, send her an email about exactly what you feel, and get right to the point. i've done it twice. worked both times. make sure you are clear. and look, you are good enough for this, and your feelings do matter even if you think they don't. If she makes fun of you for it, or if she is mean to you about it, she wasn't your friend in the first place. It may hurt, but sometimes you have to take these risks. be strong and send an email :) you'll thank yourself afterwards