worried baby isn't getting full

A
My baby is 4 weeks old and I feel like she's never satisfied. I'm concerned I may be making too much of the skim milk. She has several pee and poop diapers in24 hours. The past few days she's had a greenish Bm or 2 (it's mixed with yellow usually ) which I know can mean an inbalance. I have not called the doc because after I see a green it's usually followed by several yellows. This morning it was pretty dark green, the bm before it was yellow. She takes forever to eat. Sometimes she will stay on one side 20-30 min. She dozes off a lot which I know can mean a shallow latch but it's getting better. I try to compress my breast the entire time to make sure she's getting it all. She got 1.5oz out of one breast yesterday while at support group. I just feel like if she's not eating or sleeping she's crying. I'm not sure if it's hunger or pain but I always offer the breast if nothing else seems to calm her. She's also only gained about 4oz in a week which I don't think is good. She is taking Zantac for reflux symptoms . I haven't given anything for gas but she does burp and fart a lot. I'll even make sure to burp her during the middle of a feed to wake her up a bit and hopefully reduce any pain. I'm getting so frustrated because I feel like the LC and peds just don't have answers 😞 I don't want to give formula unless medically necessary. I want to enjoy these last 8 weeks of leave not worry if my baby is starving or in pain 💔