feeding problems, please help?

so my baby is almost 5 weeks old and i exclusively feed. her poop turned green and mucusy and she has alot of gas and shes constantly pooping. i read that his means she has a hindmilk/foremilk imbalance. she has almost every symptom that they listed. i suspected this a few weeks ago but the dr dismissed it as colic, but now her poo is green so im sure its an imbalace. how do i fix it? im trying to feed on the first longer and i know when i have the letdown bc i an hear her swallowing alot but how do i know when to switch? please dont put a time limit either bc all babies are diff and some eat fast or slow. i notice that after awhile she seems to get upset but im not sure if its bc theres not enough milk or bc her tummy hurts bc of the imbalance (she gets bad upset stomach aches bc of it). how do i ensure that she gets enough hindmilk? also, if she gets enough hind milk on the first and is still hungry and i switch her but she does eat long, then will she get too much foremilk on the second ? also, does my eaing habits affect my foremilk/hindmilk poroduction? like does drinking too much water make more foremilk?