You're not the only one struggling with day 2s.
I know its frustrating, but in these situations, try not to beat yourself up about it. Keep learning about women and keep playing the game. You also seem to be very worried about the bounce back, the move you will use to get her back, etc... worry about the interaction instead.
You said it was a fun/flirty date, but she was obviously not as into it as you were. Admit that to yourself, and learn from it!
1. Learn to record your dates/approaches. A simple iPhone using the voice memo app and a headset can serve a discrete way of recording a date. This might sound creepy but if you're getting frustrated by your dates, it serves you to go back and listen to moments during the conversation where you were stumped, moments where you could have expressed yourself a little better, etc.
(great headset for this: http://amzn.to/167JR13
2. Get instant dates! If your approach has hooked, and the girl likes you, use that momentum with her to take her for a coffee right there. You might think this is pointless because you're not going to get any pussy from your instant date. Well that may be true, but chances are if the girl wants to see you again after a successful instant date, she is seriously considering you as a romantic partner. Watch Jon Matrix's instant date with the french girl in Effortless. So far all of my big daygame "closes" have come from instant date girls.
Instant dates are also a good way to go on a date if you've got no leads and some free time after work