repeater

So this girl and I have been dating for almost two years now. I'm a senior in college, she's a year behind me. Things were going great until last semester when we both went abroad, both to the UK but me in Scotland, her in England. While there she really grew a lot as a person and became a lot more independent. We saw each other for about 4 weeks total throughout the 6 months we were there and things were still pretty good. Now that we're both back home for the summer before our school starts again, me in DC, her in Ohio, she said she wanted to take a break. I still am in love with her but there wasn't much I could do about it so we're on a break. During this time she still says she loves me, can't wait to get back to school together, and she's committed to the relationship. She just said she was having a lot of fun with her friends there and didn't want to have the responsibility of having a relationship. I could understand that, she told me it wasn't about wanting to be with other people, just that she didn't want to feel like she had to come home to call me all the time. So we started talking once or twice a week on the phone and I was probably pretty depressed but that's only natural right? Anyways, my dog died on friday and it was a big deal for me so I call her. We have a good talk but I was really upset and was bringing up stuff I know I shouldn't have, like bugging her about her friends trying to make sure she wasn't dating or whatever. I still think I have good reason to think that she is but I apologized for bringing that all up and we agreed to talk on sunday because she said she'd be home and really wanted to talk. When I call her house on sunday she's not home. I call her cell phone and she's turned it off. I call her house later she's still not there. I'm kinda pissed that she changed her plans but only because she didn't just tell me. If she had done that I would have been find, I figure she'll call me or email me the next day (yesterday). I call her in the morning and she doesn't pick up her cell phone. I call in the afternoon and it's off. I call her in the evening and it's still off. My thoughts were I'll try calling her again this morning, and if that doesn't work just assume she's probably done with relationship. Am I totally over-reacting to think she's doing this all on purpose? Is she avoiding me? I just don't understand how we've gone from a great relationship, a break where she said I can call her anytime I want, to her not answering or turning on her phone. Any advice?