Pumping breast, feeding, poor diaper output

My LO is 38+3 weeks. While in the hospital with consult from the LC, she confirmed that everything seem to be right, latch etc. But the LO was still coming to my breast every hour. I've had two pretty bad days where he latches and will feed every hour. But very fretful, doesnt sleep well, gassy. i noticed that as the days go by his feeding have gone from 10min to 5 mins. He likes the right breast, doesn't take to well to the left. Ive been really concern because he has had no stools since Sat. and had only 2 good diapers. I called my peds helpline who says to go ahead and supplement with 1/2-1oz of formula after taking him to breast. i went ahead and did that and have notice that hes been less fretful, sleeps easily. Theres was also an incident where I took him to breast, he ate, was fretful so I gave him supplement, but then he wanted to go to my breast about 1o min afterwards then he fell asleep. Theres also been times that he goes to my breasts but will not take the supplement. I also started to hand express and manual pump just to get my breast to soften. I only pump about 3 minutes on each side and will get 30 ml of breastmilk. Why would my LO not be having wet/diapers even when it seems like hes getting enough milk? I have a call out for a LC to come to the house and help me. I also am trying to ask the MD could I just go ahead and supplement with what I expressed or continue with formula? It seemed like she wanted him to get the formula? Why is this? I know breastfeeding would not be easy but im so confused!