Forget about it, you dated her for 1 week. Maybe she just didn't feel love for you like for your bestfriend.

When you say ex of a week, do you mean you broke up a week ago or you were together for a week?

Either way, don't fuss about it. If their relationship is more successful, it means they were a better match than you.

Well then it's a month, get over it.

If it was only a month then don't be so dedicated to it, what you want to realize is that if she found a better match, then it's over, and nothing you do will make it better, if anything it will make it worse. Let it go dude, it's not like you invested a year in it or a ton of time, but I get how you feel, rejection hurts. But your the only one that can change how you feel about it. Good luck

She wasn't the one for you, don't worry, it wasn't meant to be.