Hungry or fussy/gassy?

How can you tell if baby is hungry or just fussy/gassy? My baby is 11 days old formula fed and is really gassy and has trouble pooping. He sucks on his hands, throws his head side to side trying to look for something, starts getting fussy and starts grunting and crying. When I try feeding him he takes the bottle right away like he’s starving and starts sucking the bottle aggressively then starts to fall asleep or he starts pushing formula out of his mouth while feeding. I try to feed in 2 oz every 2 hrs sometimes he’ll take the whole bottle and other times he’ll only drink 1.5 oz or sometimes even

.5 oz. I don’t know what to do I’m so stressed about him and his eating. His birth weight was

7.11 his first checkup he lost 5oz and his 1 week checkup he only gained back 3oz. Am I to focused on his eating? I have a app and try to track everything but I feel like it’s making me crazy and even more worried about getting him to drink his whole bottle. Sometimes I don’t even wait for him to cry or get fussy for food I just see thats it’s been 2-3 hrs and wake him up or try to offer the bottle when he might not even be hungry. He has enough wet diapers and poops at least Twice a day if he can. Does anyone have any advice for me I really need all the advice I can get.

-stressed out first time mom