My Blood Flow && Cramps ??

So im really scared right now becaise my flow is entirley to heavy . I've had crampss sice yesterday . And i wore a tampon and a pad together and the tampon was full in less than hour and my pad was almost full . So i am really scared and i told my parents i need to go to the doc .... But what if they dont take me as soon as possible and it gets way out of hand . Im really scaredd i think i may have a disease or sickness or something . Pleaseee tell me what todo !