To love is to hurt. See love is like going into X-Box LIVE Halo. You're there to have fun but you know you're going to encounter a metric ton of trolls that will consistently remind you that they are better than you and that you suck (even if this isn't true).
When you date, you will get dumped or get rejected. You just have to grow some thick skin and accept you have lost this girl for "more-than-friend" relationship. There's no gain from despair over one defeat. You see that small blur and your blog title don't match in that you haven't been looking for other girls because you've been stuck on this one particular girl. It's time to move on in terms of you two being in a relationship (if you can stay as friends with this girl without your feelings getting in the way, then more power to you).
There's many girls out there. Don't limit yourself on what you perceive to be the perfect match when you have not dated every single girl in the world for an accurate comparison.
You improved one thing or two but what probably happen was that all your other "dating skills" went down the drain temporarily. It's a normal bug of the learning process in that dating is a dynamic process requiring lots of skills at the same time and the human mind can only manage to do somewhere between 5 or 9 things at once. Once you start pushing a new skill in, something starts to slip out and you wind up with this confusing combination that "feels different". What the positive thing here is that you are improving what you wanted to improve. You have to integrate it with the rest of "you" in perfect harmony.