I've been in this situation myself -- it sounds like she was there for you when she needed you but now that she has a boyfriend, you have been marginalized. Unfortunately, a lot of people are this way, and I've had this happen to me on more than one occasion. If I were you, I would basically stop investing in the friendship, because it seems to be an ongoing source of distress for you. Do a cost-benefit analysis -- ask yourself, are you getting enough out of the friendship to justify the chronic feelings of rejection that you are experiencing? If the answer is no, then it's time to move on. Just stop calling her. Use that energy that you would otherwise spend on her toward developing new friendships with people that actually reciprocate.