@Recycledblonde
Just go up to A&E. .Knowing how busy 111 are you'll wait ages for a call back. If he's sleepy with reduced feeding then they'll want him seen anyway.
I would never tell someone not to go to A&E, however 3 different readings like this without a test against anyone else wouldn't have me running to A&E.
OP can you check yourself and the baby a few times? Call 111 meantime