Well this could be for many reasons. perhaps you have done something to wound her trust in you? or maybe she is going through a hard time and may need your help. it could be many things but what you should do is talk to her about it. Confront her about this feeling and see what she says :)
Maybe things are okay, and she hasn't noticed that she's drifting away from you. Try and talk to her about it, & if she really is pulling away from you, find out why. If she won't work with you at all the relationship isn't worth it.
Get Matched With a Therapist If you would like real online counseling from trained, Licensed, and Certified Professionals, visit our Therapists section to take a questionnaire and be matched with a counselor that's right for you.