Definitely not normal

Hi, I'm in sort of a weird situation, i've been on my period for a little over a month now and at the beginning it was heavy and then it got lighter and now it's back to being heavy again. I'm not sexually active seeing as I'm 16 years old and I'm not on any type of birth control. I am going to the doctor the 27th but I would love to know if anyone has had something similar... I'm super worried