Formula transition how to tell if hungry?

KelseyL11511

I started out BF for the first 4 months of my LO's life, but had to transition to formula a few weeks ago (right at the 4 month mark). We are now exclusively on formula but my son's schedule has changed. He used to eat, have activity time and then sleep (very much a "Baby Whisperer" baby) and would eat every 1.5-2 hours with BM. But now, he'll get slightly fussy at that time but not be hungry. I know formula takes longer to digest than BM, but I can no longer tell what his hunger cry is. We got into such a routine with BF that I knew when he was hungry right as he started fussing but the formula has changed all that. Anyone else have the same issue? About how long did your cycle switch to, from feeding to feeding? Thanks!