No poop!!!!

My son is one week old today. In the hospital before discharge, he only pooped twice. He didn’t poop again for 3 more days (on day 5), which was still black & sticky. Several hours later, he pooped for the 4th time which was a dark brown color but leaning towards streaks of green. Now it has gone another 24 hrs and no more poop. So it’s been a week and we still haven’t reached the seedy mustard poop stage. His little belly gurgles quite a bit and he passes plenty of gas, but no poop! I plan on calling the doctor in the morning (it is 1am here), but just wondering if anyone has any similar experiences with their week old baby. By the way, he doesn’t appear to be in any distress, but from what I’ve been reading, he should be pooping a lot more than this by this point in his young life.

Eating-wise, he was getting breast milk up until 2 days ago, but he lost a significant amount of weight at his first doctor appt (which is when poop #3 made its appearance). So now we are supplementing with formula to get his weight back up. Right now, he is asleep peacefully in my arms after eating (cannot bear to put him down because I’m just so worried about his weight issues combined with the no poop as well as a MASSIVE vomit 3 feedings ago).

Any insights?