A: You don't love her. Understand that first, then realize you're acting like an AFC (google it if you don't know what it is, lol). It'll help you out a lot, man. Good luck.
A: Don't suck up to your girlfriend, that's not what they actually want. Be your own man, don't feel the need to validate yourself. Save gifts for actual occasions, like an anniversary (6 month and 1 year), birthday, valentines, etc.
A: You should've been more intriguing and not simply a one-night-flirt. Not saying thats' what you did, but it's possible you didn't have a big enough effect on her. try to establish next time that you have a connection, and she'll be more than glad to return your calls.but really, just wait it out a... more