Hi.
I've not really an advice, but just to say that DS has done the same the past two-three weeks, and he's now 18 months too. So, I also think that it's 18 months sleep regression. We had long time to go to sleep in the cot, and also EW, and, as a consequence, short nights (til 9.5 hours, one night only 8 hours!). These affected naps as well, they went from 2.5 h to 1.5 h. I've also tried every routine changes, and nothing happened.
From yesterday, things seemed to improved a bit, so hopefully we are going back to normal.
I'm convinced that it is development. For example, for naps and BT, we have been put him in the crib and walked away for months, but since one month or so he's calling us when we leave the room: not crying, only calling. We just stay out of the door saying our sleep phrase, and after a while he eventually goes to sleep. It seems to me that he's trying to stay up more because he would like to play/discover/try more and he's testing his limits.
I know it's difficult, as I was very stressed last week, but I think that we have not to worry too much and wait that this phase passes.
