Is ignoring the issue the "Christian" thing to do here?

Feeling guilty for things that aren't your fault is very Christian. Your friend is an ***. It's nothing you did. If she feels compelled to ignore you for no obvious reason, that's her problem. Enjoy your life and don't brood over people who aren't worth it. There are plenty of people who would be willing to return your affections, or at the very least have the ounce of courage necessary to confront you about whatever problem they have.