Postpartum bleeding

Cindy • I'm 34, SAHM to 3 year-old girl and brand new bouncing baby boy!
So my son was born on April 27- which was 10 days ago. I had a repeat c-section.
The nurses at the hospital said to call my doctor if I soaked through a pad in an hour. Well I just called my doctors office and the nurse there said an occasional one is no big deal- there were not clots. She said if it keeps happening to call back.
But- how many am I supposed to be concerned about? Two pads in two hours? 3 in 3 hours? 
I'm not in pain- but I do feel cramping, like menstrual cramps. My son has been cluster feeding today, so maybe that's why? 
I haven't bled this much since the first day! It's kinda freakin me our over here! 
The pic is just to show how cute he is :)