Help please?!?!? No judgements

Autumn
Okay so my boyfriend left for a med program. And I'm completely proud of him for doing it. But before he left and the whole time he was gonna I failed to feel any emotion from him. 
​I called him twice and while we were on the phone his new friends keep button in an interrupting us. He recently posted a picture on twitter of him an a friend shirtless. In the picture the chain that he wets around his neck did not have his ring or my ring on it like it usually does. 
​I feel like he maybe losing interest, or maybe I'm not being a good enough girlfriend.  
​Anyone got advice on what to do? I'm so confused.