No wet diaper in 4-5 hours help!!

My almost 6 week old baby was last fed around 11PM. Woke up at 4:00AM hungry and did not have a wet diaper when i changed her. She just ate 4oz. She was kind of fussy yesterday but I didn’t think it was anything to worry about.

No fever, soft spot is not sunken in, skin reflex is normal, she isn’t lethargic or anything out of the ordinary for a 6w old, no sunken eyes..

Any other signs of dehydration that I need to look for??