I don't know what I did to be honest, I wasn't touching her for long (interupted)... She said I hurt her, but only once (maybe I hit the part where the urine comes out of?).

A few hours later, after she was all aroused again, she kept complaining that she had the sensation that she needed to urinate, yet had an empty bladder...

Is this normal, or did I do something... Really bad.?

If you confused her urinary tract and her vaginal tract, you don't deserve to be fingering her.

Relax, you didn't break her. G-spot stimulation can cause you to feel like you have to pee even if you don't, and if she's not used to that kind of stimulation then the g-spot can be very sensitive and cause that need-to-pee feeling.

A few hours later, after she was all aroused again, she kept complaining that she had the sensation that she needed to urinate, yet had an empty bladder...

I've read from a couple of things on here (check out some of the user submited files and shit) that that's what some chicks feel like before they squirt. Or you could be fingering her pisshole.

Whatever, she said it went away after she took a piss herself...

Maybe I just need to go a bit lower. Ah well, at least she loved the rubbing part of it.

As far as I can tell, girls always have to pee after sex. Or sexual stimulation. Its just a fact of life.

Sounds kinky.

That would be... Pathetic...

its true.

Guys have to pee, too, after sex... Right?...

I don't usually feel the need to pee after sex. But sometimes I will if I can, just because i'd rather be dripping urine then sperm.

And now for the intelligent answer:

Could be cystitis. Here's a wiki fi you want to know more. http://en.wikipedia.org/wiki/Cystitis

It's pretty common - my gf has had it a couple of times. No biggy just get her to go to the chemist and get some stuff for it and it'll be better in no time.