Constipation

I’m 11 weeks postpartum and am really constipated. I used to go like 3 times a day and now I go once every two days. Every time I go I’m in so much pain from hemorrhoids and tummy cramps but pebbles come out. I had a C-section and quit breastfeeding on Tuesday. I drink over a gallon of water every day and take fiber supplements. I’ve tried stool softeners and nothing is working. Any advice or experiences?