I can so sympathise and understand where you are coming from big HUGS! It can be so frustrating when a routine seems to be working and you finally think you've cracked it then they change it up again! My LO turned 14 months on the 29th Aug and we went through a particular funny phase again with sleep AGAIN.
Up until then he had been consistently doing 1 nap 12.45 to 2.45/3 and BT at 7 sleeping till 6.30/7 I know this seems a late start time for a nap but he just prefers a long morning and shorter afternoon A time, things went wonky about 3 weeks back and EMW/OT started to creep in which I think was partly due to a WW which is what may be disrupting sleep for you too? If he's full of cold it could also be that or his teeth. As he comes into a lighter sleep he is maybe in some discomfort so can't quite get back to sleep?
On what I hope is the otherside we're now only getting 1.20/1.30hr naps but he seems to be managing just fine to 7 BT (other than the 2 days he goes to nursery) we do 6.30 BT on those days and get 12 or 12 1/2hr NTS
He would take a nap in the car anytime from about 9.30 if I offered it to him, I just try not to drive too far, I now find even 10 minutes CN and he refuses to go down until sill o'clock in the afternoon.
I've heard other mums mention that for some their DTS reduces around 13-15 months and then it increases again around 18m when the next big leap comes and language takes off.
I would probably wait until you think he's over his cold and then maybe think about pushing the nap out by 15 minutes and keeping the length the same in the first instance before you trim it?
