Is Heavy Bleeding During Periods Related To Cervical Problems?

Hi Doctor, I'm 28 yrs old sexually active and on the pill. I normally never have very heavy periods but for a few months I've had light brown spotting before my period which I'm aware is a slow start however today, just now after 2 days of light spotting I came on properly with very very heavy bloodflow and brown blood. 2 years ago I had a cervical smear with irregular cells but I didn't get them re-checked. Is this normal with regards to my period or could it be linked to the cells? I'm concerned as it's very heavy. Thanks.