How long will it be until i have a normal flow?

I got. My 2nd period on Thursday and ever since its been pretty heavy. I only have regular tampons not heavy flow tampons. But I am confused because 1 how long will it be until I get a regular flow and 2nd I had bad ranch yesterday and my tummy started hurting and it felt like I had to diahrea badly. But I never wuld diahrea. And my mom thinks I have food poisoning. So is that cramps or actualy food poisoning