I sincerely believe in what I'm about to say. The best thing that could happen here is if she stops replying, but YOU take the initiative and stop caring. That means you forget that she stopped replying and move on.
The reason why guys who don't care are successful is because they don't fall into typical male habits. They're comfortable with approaching a girl and talking for five minutes, and then leaving if they need to and never looking back. I rejected and refused the best looking girl I've ever met for various reasons. I regretted it for years before I was the way I am now.
Now? I'm glad it happened. Great character builder. I have some issues of my own but I can say with absolute confidence that I'm VERY comfortable in my skin. So yeah, chill out. Keep working out, keep going out, and keep yourself happy and positive!
That's it for the night, I'm off to sleep. Good luck, dude.