Starting to feel like a failure šŸ˜ž

I'm having some difficulty breastfeeding and it's starting to really get me down.
I have a snacker who isn't getting the fatty milk and her poop is green and stringy because of it. She seems more fussy lately too. I'm breastfeeding, pumping, blocking...
I know not everyone's breastfeeding experience is a walk in the park, but she's just so small and fragile. I just want to be sure she's getting everything she needs and want her bowels to go back to normal.Ā 
Any suggestions?Ā