Don't panic
It's only been a few days and there are very many things that can (and WILL) come along to disrupt a lovely sleep routine. Try not to worry about a little rocking, doing this once or twice isn't going to become a major prop, mainly because you are aware of it. I rock my LO pretty often for comfort but he still goes to sleep 90% of the time on his own, the other 10% are the off days when he is poorly, teething etc and needs a little more mummy.
If you can do it whilst he is still in the cot you might feel more confident about it. So PU if necessary but if not then try rocking in the cot with a firm hand, this way he is still feeling the mattress beneath him and you can reduce and stop more easily. You can do this through the transition to extend the nap.
My first thought is that the night wakes may have been due to teething or gas pain, do you think this might be a possibility? It's just that sudden NW from a good sleeper is generally for good reason. This could have been disturbing his naps too. It isn't just UT that will lead to waking at transition, pain or other discomfort can do it too, teething, too hot, too cold, gas, reflux etc because as LO moves to lighter sleep at the end of a sleep cycle they feel the pain/discomfort and it wakes them fully so they are unable to transition into the next sleep cycle.
My next thought is that maybe (just maybe) your A time on your good naps might have been a little long leading to those extra long naps, and cutting back just a little could have reduced the nap, made it a little earlier in the day and you might then have fitted a CN in for a slightly later BT. The 'original' NWs might have been down to OT. Maybe just something to bare in mind for the future - but I know you must have been loving those long naps eh?
OK, so here is the link to recommended A times, bookmark it.
http://babywhispererforums.com/index.php?topic=64158.0You'll see that at 5.5 months we'd be looking at 2hrs 15 to 2hrs 30, although the upper end is moving more toward the 6month mark.
I would be tempted not to up the A just yet but to check for other problems, it's only been 4 days, those recent NWs sound more like illness or pain to me.
Does he have any white caps under the gums that you can see or feel?
Any chance he has a cold coming on?
If you can rule out all other possibilities then maybe up the A a little. You need to stick with a new A for a few days to see results, you won't always get a longer nap from the first day of increased A and the temptation might be to up it again the next day but this is what can lead to major OT. Take it steadily and you'll get through it. If your LO find change difficult then only go up in 5 min increments, stay there for 3 days, then up 5 mins, stay for 3 days.
