Relationship space or beginning of the end? Confused?

Me and my girlfriend have been together for 2 months now. In the beginning when we met we both agreed that we found our soul mates, true love and the one we would marry. For the past 5 days she has become distant all of a su. Intially she told me just to give her a little space.(Not cheating) She just claimed to just want some alone time with herself to preserve her identity as a independant women. Last night we spoke and she is now telling me she does not know what is wrong with her and it is bothering her that I am hurting cause of her recent behavior. She stated that she feels resentful in a way becaue i may have smnothered her. She continusoulsy states that she is not breaking up with me or plans to and loves me.. She has started a new birthcontrol (ortho trcycline). I feel it may be that, because 5 days of her taking it this all began. Basically i am looking for some help as to understanding why she has pushed back when everything was great. Any advice would be great. Thank