This sounds like classic anxiety to me. I get more anxious in anticipating an event than once it comes to pass. Even if what comes to pass is terrible; however, much of the time, I anticipate the worst and it does not turn out that way.

If she doesn't want to advance your relationship then you will just have to grieve it --you are anticipating the worst either because you sense it or just because you are preparing for the worst but it might not go that way. You still haven't met. I am glad that you are meeting her. I think you will find out whether or not it is going to work then. Try to just wait and see. Try to distract yourself and think of other things (watch a movie) in the meantime. You are an overthinker and perhaps obsess about some things? Whatever happens, I bet she may still consider you a friend. I don't doubt that there is some sort of connection. My advice is to try to accept what is--whatever happens--we can drive people away if we expect rather than just accept what they have/want to offer. Enjoy her visit as it comes because she is traveling so far just for you!