Why is she neglecting me all of a sudden?

[Dexter]

I'm 20 the girl I like is 18 she lives a few hours away. For some reason she replies to my text and phone calls less frequently and I only contact her every other day . She will usually reply back saying she is sorry and she is really busy and claims she rarely checks her phone but yet I can clearly see she is on facebook using the mobile app on my chat sidebar. She still likes my pictures and statuses. My theory is that she still dealing with her ex. She is just out of high school and 3 months ago broke up with her high school sweetheart so she could still be getting over him and that is why I am not on her mind as much so I might just be a little selfish because I am craving for her attention. Could it be she isn't interested or she has other things going on that she just needs space. Im willing to do anything to show her that I am worth pursuing I might give her a surprise visit on new years. When she lived closer to me she claimed we were just friends yet gave me some obvious signs of attraction and I am getting the vibe she doesn't thinks she is good enough for me because we come from very different backgrounds.