She suddenly stops talking to me, what am I to think?

We've been getting to know eachother over the last couple months. She was trying to rush things and I was taking it slow because I don't want to get burned again. We'd talk nightly for hours straight and she was always happy when we talked and texted. I really changed and became a better person when I met her, and was cautious because I knew something like this would happen again. Maybe too cautious. After her birthday a couple days ago she won't talk to me and only texts me "I cant talk now. Sorry.". She said she won't be in cl this week and said the reason was "family deaths" but won't say anymore; this is all through texts. She just seemed so interested and we could talk for hours. One of her biggest things was honesty and now she wont reply anymore than "I can't talk now" or "I have to go". And I can't just "move on" from this girl, going from talking for hours about hour lives to no contact just like that. I don't want to become depressed and bitter but it's hard now.