confused

Hi ladies, I am a little confused. My period is normally heavy from day one through to day 4/5 and it's very painful like on a scale of 1 to 10 it's a 10. My period started yesterday and it is very light and the pain was like a 1. Is this normal? Has anyone gone through something like this before? I keep thinking the pain will kick in and it will get heavy but so far it isn't.