What Causes Bright Red Heavy Bleeding?

I had a c-section in April and started taking Cerazette about 3 weeks ago. Thursday I started having spotting and since then the bleeding has gotten progressively heavier. Today I soaked a tampon and bled through a panty liner, then changed the tampon and started leaking again after only 3 hours. The bleeding is now bright red. My periods have never been this heavy and have never been bright red blood - it has always been dark red or brown. Should I be concerned?