I would definitely go to see your pediatrician
or adolescent medicine doctor
about this issue right away. My main concern is that if your period has been going on for 10 days without slowing down, you might be losing quite a bit of blood and could end up dangerously anemic. Your doctor will be able to perform some blood tests to see if you have evidence of anemia. If so, medications may be needed to help stop the bleeding
In particular, if you feel very fatigued, light headed, short of breath, or dizzy, these could be signs of serious anemia. Also if you are changing your pads very frequently, or passing large clots of blood, these are also signs of serious bleeding. If you have any of these symptoms, then you should not wait to have an office visit with your regular doctor but should go to an emergency room right away for more urgent evaluation.
If on the other hand, you feel generally ok and are just having some spotting, then you can probably wait for the next urgent care slot with your regular doctor, who can help you figure out what to do.
I hope you are feeling better soon!