green poop EP

My baby is becoming more constipated and is having watery green poops lately. I've been pumping for 5 weeks. (She's 6 weeks old this week). I read she's not getting enough fatty hind milk. How do I make my body make more? I tried pumping longer, no change. Anyone else had this problem with baby under 6 weeks? What did you do? Did it get better as she got older? I do give her formula 2x a day as well. Any suggestions or similar situations?