Paul, I wish you all the luck finding a partner who will give you their time and treat you with love and respect rather than the uncertainty that this lady has shown you. She is not ready for a relationship and understandably she has other priorities at the moment. The way she treated you when you made the effort to attend the holiday on platonic terms was neither nice nor respectful.
You haven't mentioned how you feel and what you want? Are you still keen to persue this relationship? Would you be interested in being second best for a while and dropped like a glove again?
Learn from the past, take a deep breath and move forward. Love comes when you least expect it, so don't tie yourself to something that will not work long term.
If you can't look at her and imagine looking into those same eyes in fifty years time, then she's not the one.