from your statement the cause of pain and bleeding was due to remnants of after birth
upper abdominal distention may be due to flatulence
may give rise to wind pain
lower abdominal swelling may be due to sub involution of uterus or it may be due to lack of abdominal muscle tone
in postpartum period'
there may be lactational amenorrhoea but pregnancy can occur in this period also.
if you are having problems please consult your doctor