POSTNATAL PERIOD HELP

So I'm 5 months PP via cesarean. My periods have been EXTREMELY heavy and irregular. I can have a period and then 10 days later get another one... its soooooo heavy. Like seriously heavy. I soak a tampon in like 20 mins. I soak through a pad also. I'll change just before I sleep and then by morning I'll have leaked through.. it's also painful. Like I get severe cramps.. when I lean forward it kills! Is this normal?? Any advice or similar stories??