My 15 month old is on 1 nap & in the last 2 weeks his nights have shortened from 11-11.5hrs down to 10-10.5hrs & I cannot seem to fathom out why. He is waking up unhappy in the mornings & has huge bags under his eyes so I don't think he's well rested.
He's been an early waker for a very long time & b/c of this, when we first switched to 1 nap it started at 10am, & so we let him sleep & then put him to bed at 6pm. For the last several months I have been trying to gradually push his nap out later & every time we get as far as 11.30am/12 midday & his BT gets to 6.30/7pm he starts to wake later & I think 'yippee - we've cracked it!' & then within a couple of days its back to 5am wakeups.
I've tried keeping nap & BT at the same time but he winds up more & more overtired so I end up bringing the nap earlier to 11am & bringing BT earlier to 6pm. But then we are stuck back in a cycle of early wakeup, early nap, early bedtime & I have to push it out all over again. This has happened so many times now I've lost count. Most other babies who are on 1 nap seem to take theirs after lunch at 12.30-1pm but we cannot seem to get there.
DS is waking miserable in the mornings & in the last 2 weeks has been getting up around 5am. He was napping 11.30/12-1.30/2 with a 6.30/7pm BT & was getting up just before 7am. And suddenly 5am wakeups struck. Now he's napping at 11-1pm with a 6pm BT which of course means he wakes earlier.
2 nights ago he slept 12hrs & yesterday got up at 6am (catch up from all the short nights) & so we did nap at 11-1 & BT at 6.30. Today - awake at around 5am. So he just about made it til 11am for his nap today & was very very tired. I'm certain he'll probably need 3hrs nap after being up so loong but if I let him sleep we'll get another 9-10hr night. We have absolutely no consistency to the length of his nights & so it makes it very hard to keep the rest of his routine consistent.
Does all this sound like my LO is just low sleep needs? I would totally accept that if it were'nt for the tired eyes & him waking unhappy. 
How can I encourage a later WU?
Can anyone give me a plan for pushing his nap later with suggested nap & BT's? I have a feeling its the duration between nap & BT that may need to change - but which way - longer or shorter?
Does it look like he need even less day sleep than he is having now???
Can anyone show me/point me in the direction of a good routine for a LO of same age?
Sorry for the epic post but I'm at my wits end & so tired of all the early mornings.
Would really appreciate any help/advice anyone can give.xx