Feeding routine for newborn?

Ji
I am nursing every 2-3 hours, 3-4 at night. She will sustain a latch for only 5-10 min on each side. Weighed her after a feeding and she only took in 4ml. Granted it was a sleepy, lousy feeding but she hadn't gained anything by her 5th day of life. So after I nurse, I bottle feed her whatever I was able to pump from my last session and then I top her off with formula. Lactation nurse said she needs about 70ml/2.5 oz each feed. After I feed her I then pump for 10-15 mins and save that breastmilk for the next feeding. I've done this for a day so far and at first my supply started to come back and I could pump up to an ounce but now it's been down the last two times I've done it and I've only been able to pump 10ml/20ml each time. :/ And I know she didn't get much from nursing those two times either. Just wondering if maybe I'm pumping too much/too often? Goal is to get my supply back up so we can go back to breastfeeding only! TIA