about 3.5 hours max during the day
I had the same with my first, was awful because whenever I asked any HCPs how long I should let him go between feeds, they'd say "no no no, no routines, feed on demand", but my LO didn't demand
probaby down to a combination of jaundice and pethedine during the birth? I dunno.
I found BF peer supporters the least helpful sadly because whenever I asked about timings they'd get on their anti-routine high horses!
anyway we settled on waking every 3 hrs during the day, and allowing one 5 hr stint at night
was hard though - we did all the things you're doing, nappy change/strip and back on. Just keep it up. LOTS of skin to skin'll help too, do you have a stretchy sling? that way the LO can always smell you, these are good for newborns: www.victoriaslinglady.co.uk/
and co-bathing is good for feeding, the bath wakes the baby and the warm water helps your supply
we got there in the end, LO gained weight well and we BF for over a year