REALLY heavy period? Is this normal??

My periods are decently regular, they usually occur every 19-22 days. Every time I get one it is a medium-ish flow for about five or six days and then a light flow for one or two more. This time I got my period right on schedule (day 21 of the cycle) and with all the normal symptoms that I have: cramps, back pain, emotions running high, etc. But the flow has been very heavy, enough that I have to change my pad every hour (I don’t use tampons) and it’s been staining my underwear and pants even when I wear a pad. The color is normal, everything is normal, except the amount. I don’t know if this is normal or if I should see a doctor or...

Advice is appreciated. Thanks