That'll happen. When a girl pursues you quite hard for sex, especially if she hardly knows you, usually it's an indication she's ruled you out as a boyfriend and just wants a hookup.
There are some things you can do to raise the odds you convert her to a regular sex partner. But in the "she's firmly in control of the seduction" situation, your odds aren't great. She's calling the shots, she knows what she wants, and she's already made her mind up about you... take it or leave it. Can always ping her every so often, and she might come back to you again when she's in the mood again. Do that a few times and maybe you slip into something more regular with her.
Don't know if you're familiar with our longtime contributor Alek Rolstad, but he's an Oslo native (primarily a night gamer). We have tons of content here from him.
Day game confidence... well, the anxiety around approaching is standard approach anxiety, whether you experience it by day or by night. Every guy (just about) must deal with this. It's harder to overcome in day game, which is why you see so few day gamers. On approach anxiety, we have a bunch of tips and guides by various authors:
Also probably useful:
A few pieces on getting started with day game:
(you can find more on day game if you use the search function... but I'm sure that's enough to get you started!)
For meeting women during daytime, sure, cafés can be okay spots for this. You'll find the most traffic / highest volume on some streets, at certain subway stops, and in some shops and shopping malls. University campuses can be okay if you're not weird about it (i.e., not a guy who'll freak women out and get reported and run out of there!). Some more spots here:
Hope these all help!