Oh sorry were you hoping for some sympathy?
I just have an issue with guys like you that even when they are told specifically to leave someone alone still think if they just can get them to change their mind and see them one more time they will come running back. It's stalkerish and creepy.
Why are you even seeking advice on this? - No-one is going to tell you to keep trying when it's obvious you were nothing to her but a casual friend, you wern't dating, she has a boyfriend and wants you to leave her alone.