<human>: Can you give me the gist of the text in a nutshell?

In my life I've had three serious long-term relationships (2 years, 4 years, and recently 2 years with about a year in-between each), and dated casually a few times, with varying levels of success (some lame dates, some that went ok, one that turned into a short lived physical relationship). 

The serious relationships I've had I feel like I kind of "fell into", there was a mutual attraction and the proper social setting that I could make a move and feel confident about it, I was around friends, not "out in the wild". That being said, I broke up with my last girlfriend a few weeks ago and when women approach me now, I feel like I turn into a babbling doofus. 

There's really no excuse for this when I look outside myself, a few days ago I had a woman approach me me at a party and before she did I heard her whisper to her friend "He's so handsome!" I immediately felt nervous, and while I was interested, I clammed up emotionally and now I'm kicking myself as I clearly could have moved forward, and wanted to, but I essentially ran away. It feels childish, like a silly mental block, but when I look back on how I handled it I realized it was a clear lack of confidence (or intimidation). I don't know if I'm out of practice or just feel insecure, but either way, any suggestions on how to move past this, or even stories of people having gone through similar stuff (guys and gals!) would be great!
<bot>: Broke up with 2-year GF a few weeks ago, now when women try to flirt I freak out and get nervous. How do I get past this/share your stories to make me feel better.