Pubertyy question plz answer?

im 15 and never had my period before i've been having pressure feelings on my lower stomach all day on the left side its been like that ever since last night i noticied theres black in my discharge but it may be lint from my black sweatpants but tonight i have a bunch of discharge it was clear but its yellow crust now i keep getting a bunch of headaches,i dont feel like myself at all and my are really sore do you think its my period coming and like how soon i wanna get back to normal before wednesday because i gotta go back that day