My immediate hunch would be "OM contact," but it could be simple Martian rubber-band pullback. Although that's normally more associated with men, some women do it too; does she often pull back emotionally after getting close to you?
If you text her, I wouldn't do a "how are you"; I would do more of a "Tristan's Getting-A-Life" one, such as "Hope all is well with you; just wanted to let you know you may not be able to reach me for a few hours this afternoon, as I need to do something, but I hope you have a safe trip" -- or something similar. Be mysterious.
I know you're anxious, but don't assume the worst. Several months ago, two phone #s kept showing up on my wife's cellphone bill, and I thought "only ONE Of them can be her new divorced GF," but it turned out that one was the woman's home phone, and one was her cellphone.
