Brown/black blood or discharge

this has been happening for months but not everyday. i’m 17 a virgin never even had my first kiss. i’ve been having periods sense i was 11. about 6-7 months ago i started having blackish brown discharge/spotting it was always a couple days after my period only lasted about 5 days at a time. this stated after i started wearing tampons for the first time. but this month after my regular period ended it started about 5 days after and i’ve been spotting over 2 weeks almost 3. it never really has abnormal smell doesn’t hurt to pee or itch. i shower everyday and make sure to wash everything good. My mom would never take me to the doctors before because she would say it’s old period blood just leaving my body late it’s nothing to be worried about. but i don’t think that anymore. i have a doctors appointment but it’s 2 weeks away and don’t know how to handle this until then. I’m scared to have a pelvic exam nobody has even been close to my privates parts. i’ve never put anything inside of me including my hands or fingers other then the tampons. i know what to expect for the most part but I’m terrified of the feeling and it hurting. I’m also scared of there being something seriously wrong and it not being fixable. i know there’s nothing i can do till my appointment but my mom is not a good help and i’m not comfortable talking about this with people i know. i know stressing myself out isn’t gonna help but it’s hard to keep telling myself i’ll be okay not knowing if it’s true or not. i guess i just need someone who’s been through this to help me feel better.