antjs,
I get where your coming from and I've found something that works for me. Take a look at this current "dating" situation as if it were a friend telling you the story. What would you say to your friend? Probably something along the line of "If she can't see what a great guy you are, her loss, move on!" "it's her problem, not yours, don't waste your time."
Be kind to yourself and realize that you have are one of the good ones and if someone can't see that... .then... .run!

My guess is you are talking/texting this girl and putting together this "allusion" of how great she is. Then when she "rejects' you feel like crap. First thing is you don't really know her yet. You only know what you have been told, what you feel and the story you create in your head about her. The first sign that she isn't who you think she is... .would be that she isn't interested in you.

Stay strong and be good to yourself... .
Bunny