periods and pregnancy?

QUESTION: When pregnant, how much bleeding have you had? Can you be pregnant and have bleeding each month?  ( only when your period is due) with medium-heavy flow for 5 days? 
I have had 5 "periods" since I last had sex with medium bleeding for 5 days. I'm on the pill but have had pregnancy symptoms for a bit over 4 months. I have taken a couple of hpts and they were negative. 
Posted this in another group but still curious!