My daughter has a feed at 11 in the night and then does not wake up till 5 the next morning. Is it okay? The doctor says it's fine.

It's fine as long as your baby was not born premature. Premature babies need to be fed on schedule. Other full term babies are encouraged to be fed on demand. I feed my baby on demand as well but she demands every 3 hours even at 7 months. Haha. We all have different journeys.