No. Don't ask if you are still cool. Wait and see if she calls you or IMs you or whatever. If she doesn't talk to you for a week or two, call her and apologize and ask if you can be friends. I've been through something like this, except this girl pretty much ignored me whenever I tried to talk to her on AIM, for the whole summer, until I couldn't handle it any more and got pissed at her. Then I realized that she wasn't real to me, and hadn't been for weeks... That's what happens when you think about someone all the time and she never ever talks to you (though she says she likes you). It hurt to remember when she was real. I explained this to her, and she understood, and I IMed her a few times after that, but no more. I'm satisfied with the relative closure. She's had some other guy that she ignores as well, but he actually got to talk to her on the phone. Imagine that.
What I want to know is, how can you like someone and have no problem talking to him one or two times a week, and ignore him when you do talk?
Don't feel bad about it. Everyone has a breaking point. Mine is a couple months. My friend's is 6 months and counting. Yours is 6 days, which certainly makes it alot easier. Look at it as a learning experience, and know that at least you didn't let her screw around with you. She made you believe she liked you, then ignored you for a week and you let her know that you wouldn't take head games.