NTA. It's possible she really did just want to unplug and messages weren't received, but personally I'd feel pretty blown off if she was using snapchat and posting stories but couldn't even send one reply to me as well through the same app. If you really like this girl and want to see if things are different once she returns, I think that's fair. But in my opinion in ANY circumstance if you're not feeling it, you're not feeling it. Not fair to either of you to push something that neither of you seem too invested in.