Distance troubles

I'm hoping someone here can give me some advice about my relationship. My fiancee and I are currently in two different countries with an eight hour time difference, due to visa issues. We've been physically apart for 5 months now. It's been difficult, but we've managed okay. But lately, I've felt less and less like I'm a priority for her. For example, we usually call every day, but last week we didn't call four days in a row because she had other things to do. And when we do call she's overwhelmingly negative, to the point where I feel dread about what she's going to say next. She's pretty much always the one that ends the conversation and says she has to go. I'm really not sure what to do, or how to progress here.