Is she not a friend? Why ?

I have known my friend for almost 4 years now. We are both in our thirties. I have always liked her and we have shared quite a lot. I feel though at times I am the one initiating most of our contacts or meetings or things to do. She has a serious boyfriend. We celebrated New year's eve party together and we have been in contact quite a lot. Recently my boyfirend took me on a beautiful holidays and she has not said once to me if I had a good time or how was it. I even posted things on facebook and she would comment. She would comment on other peoples posts. I even sent her a postcard and most other people thanked me, she did not. I feel quite upset because she has not been in contact with me. I feel like she is distancing herself. Why has she done that? all I am doing is trying to care for her and trying to show her I really want her as my friend. My boyfrined thinks she is jelous. But why would she not even text me or email me to say hi? I initiate all of our contacts, I decided not to and now I am facing the truth by not hearing from her? Should I think that she is not a friend? Why though? I have done nothing wrong to her?