I have been using iron supplements, for the past 4 years, only recently, constipated and bloated, low due to childbirth, stress, not absorbing frm food?

Why 4 years? Iron deficiency from 3 causes: low intake, increased loss, e.g. menstrual loss, pregnancy ("lost" to fetus), urinary or gut bleeding, e.g. ulcers, polyps, tumors, poor absorption, e.g. stomach and/or bowel disease due to celiac sprue (gluten induced inflammation), inflammatory bowel disease. See MD.
Go see your DR. and get checked for intestinal inflammation,IBS, polyps/tumor,endocrine/thyroid disorder etc. Take care and God bless you! http://www.medicinenet.com/constipation/article.htm.
Iron/ constipation. Iron can make you constipated and females in child bearing years can be iron deficient. But chronic disease like crohns, celiac, food intolerances,autoimmune disease( lupus,RA) ,diet , intestinal worms can make you deficient as well . Bloating can be constipation or intolerances,infection or from ovaries./uterus High fiber, lots of fluids , F/U with doctor urgent care.