Baby became a snacker

My LO has a great latch and at 10.5w old is a really efficient feeder. I feed on demand or max 3hrs. However we’ve been having some napping issues and she will NOT eat if fussy. She will latch and unlatch, cry, get gassy etc. I didn’t think we have an issue until the LC pointed out she has only gained roughly 5oz in the past 3 weeks however she looks great and in a weighed feed had 5.6oz in 15min. Since then I’ve been trying to offer feedings more frequently which results in snacking, a few minutes here a few minutes there and the only times she would feed well is when waking from a long nap (which, with her refusing them can mean several hours with no feeding) or at night when she’s calm. Combined with transitioning her out of the swaddle she’s has gone from a good sleeper (sleep through the night or 1 wake up) to waking up multiple times at night. I don’t know what I can do about this but I am TIRED and honestly nothing frustrates me as much as offering a feeding when she constantly unlatches get fussy or crying hysterically at my boob. I have sufficient output.