OP,
Honestly what you're experiencing here is pretty common. Not really anything wrong with your vibe or what you said to her but most girls will flake out like this. You just have to keep getting more numbers and eventually you'll find a girl who really eats it up. There was a post done on this site a long time ago by a guy who's name I can't even remember who talked about finding the right girl for you is really about running all the different potential women you meet through "the machine", i,.e. you put enough inputs into the machine, eventually you'll get what you want popping out on the other end. Don't flap around in the wind and tailor your outreach specifically to what you think each girl you are trying to pickup wants. You've gotta tailor your game to what makes you happy and to how you feel best about it. If it's not what some girls like, then f*ck em. This approach will take longer to find a girl that really likes you and who is right for you, but in the end when you finally get her you'll know you've got a woman who really likes YOU, not some bullsh*t act or technique you used on her based on the type of vibe she was giving off.
For example, I'm the kind of guy who looks for an LTR. When it comes to women and sex I am happiest when i'm in a relationship with someone. Casual sex, one night stands and the bar scene leave me filling empty and very depressed. Therefore, I tailor my game to this approach. Sure, any guy can learn game and go get laid after hitting on women at a bar, but remember that women will f*ck guys not necessarily because they like THEM. There's all other types of things at play there. It's SO SO important to make sure that the woman you're with actually LIKES YOU.
For example, after a first date I will NEVER text her first or call her until she reaches back out. This ensures that the woman I had the first date with actually wants to see ME again; that she actually has interest in me, rather than PUA tactics that I could use after the first date to reach back out to her to get her interest level to keep raising.
Again, this is for an LTR. Casual sex and just getting laid are a completely different story, but my point is I do experience a-lot of flakiness from women and you shouldn't take it personally.