She definitely seems like a busy girl. & I know some of them work as much as possible because they really do need the money.
So it may not be so much as "flaky" as it is "survival".
I'd just keep the connection going & stay in contact, without overdoing it & driving her crazy. (Just pay attention The Vibe of the interaction... you should be able to tell if she's still being receptive or not.)
But sometimes it takes a little more patience & persistence with some girls. So that might be the case with her.
Still, I know the frustration with the constant plans in limbo... It DOES help when you've got several girls you're gaming at the same time, because you're too busy chatting with all of them; so if one gets a bit flaky, there are others to fill in the gaps.