Quoted:
You've built up all this attachment and emotion about a woman you barely know. And you're not 15, you're 40. I'm not saying this to be mean but you need a shrink. Seriously. They can help with your social awkwardness and help you form appropriate attachments. You could end up happy, relaxed with friends and a good woman if you work on this the right way.
Plus, and I'm not sure how this isn't common knowledge for guys, but if your confession of love blindsides a girl, or is really in any way surprising to her, it was inappropriate and unrequited from the get-go.
Telling a girl that you're attracted to her and want to get to know her better outside of the limited environment you've seen each other in so far? Fine and dandy. If she's surprised, be prepared to be turned down.
Telling a girl you love her, despite having only seen one side of her in one environment? Red flags galore, and the beginning of something that never ends well.
Put another way:
If your feelings spring from countless little fantasy encounters in your head, based on limited actual time spent together: NO GO.
If your feelings spring from things she has actually done and said, that explicitly indicate attraction to you: Continue doing whatever made her say and do those things, the rest will take care of itself.