She sounds young and not ready for a solid exclusive relationship yet.
You may be the one that she looks back on years from now and kicks herself for ever breaking up - -
when a girl says she wants to be single that is exactly what she means.
Unfortunately you risk looking way too "unable to understand what she said" if you mope, call daily, send texts or e-mails and drive by her place.
The absolute best thing you can do is Get Busy & Stay Busy and act as if you are just fine. You don't have to date anyone else if you're not up to it - but the more you cling to her the more suffocated she may feel.
Stand tall - put on a real act of doing O.K. and it will start to feel like you really are.
Come here & help support others who are hurting - you know exactly how they feel...