Breastfeeding Frustrations

First time mom here. Had my daughter 3 days ago and I've been breastfeeding. At the hospital they said my milk supply would come in soon and baby would be fine on the colostrum and her reserve fats. She dropped 7% of her body weight before we left the hospital. Since we've been home, all the day and half she's lost 10%.

She nursed for about an hour and half on and off, but remained fussy and upset. Tried patting and bouncing her to get her to burp or fart and she continued to scream You can hear gas in her tummy, and she did fart a bit but no poop. She hasn't had a poop diaper since we got home yesterday afternoon.

In all our frustration and signs she was showing dehydration, we caved in and gave her some formula (still waiting on a poop diaper). I don't want her starving and losing more weight and I don't want to give up on breastfeeding, so I started pumping to help speed things up.

Anyone have similar experiences? I don't mind if she gets used to a bottle, I just want breastmilk in there. I am planning on returning to work so this just speeds things up a bit.