[Appocomaster]

You should probably talk to her at least, and make some effort to try and sort things out. At least then she'll not stalk you, either way, and probably go and find someone else. Say you're obviously upset as you thought there was something, and ask why she didn't contact you when you got back and tell you what happened. Say that you felt she used her grandma dying as an excuse.
Of course, if she keeps stalking you after you've talked, you can always use the advice suggested above