I've been experiencing something similar with my little girl who is 19 months this week.
I do think it is a sleep regression and so I have just continued to keep to our normal routine as best I can.
Like your little one, I don't necessarily know if and when my littly wakes unless I check the video monitor.
I did let this stress me out at first, but I figured if she needed me she would shout, so now, even if I check and she's awake, I don't go get her until wake up time, which is around 6:30-6:45. If she's woken particularly early, she has started to settle back off again until get up time. She wasn't doing this about a month ago and was looking tired and grumpy in the day
Same at nap time, she will refuse to come out of her cot until she is ready so I leave her, once she's sat up, then I go get her. I believe she is just like us and needs time to come round after sleep.
With regards to bedtime issues. We've had all those you are having, but fingers crossed she seems to have settled back again.
We had a minor setback at the weekend as daddy came home for a few days after working away for 5 weeks and also the clocks going forward an hour. We had some tears and shouting and a couple of late for her bedtimes around 8pm but fingers crossed she's settled again now. I did worry that daddy going back yesterday may upset her again, but she seems OK so far and is at nursery today, which usually tires her out for bed.
Hopefully your little one will settle again. It's tough when you're used to them being so good normally.
I just aim to keep to her little routine as much as possible. I do feel a bit more confident as a mum, having managed this on my own.
It is difficult for them to let us know how they feel, with their limited communication skills at this age. I'm sure we will a whole different set of sleep challenges when they can have a conversation with us!!!
I wonder why people are keen to transfer their babas into a bed so soon. At least they are contained in their cot when they go through this regression
I hope this helps x