8.5 month old having sleep problems

[Valia]

My 8.5 month old DS has suddenly started having sleep problems. Since being a little baby we have followed a consistent bedtime and naptime routine and everything was going well.
He has never been a great sleeper and was waking twice every night but I was able to put him to his cot awake and he was happy to fall asleep on his own.
Things have started to change around a week ago when he just refused to be put down. I have tried to stay with him in the room, calm him down and comfort him but to no avail. He refuses to fall asleep and the last few nights he was going to bed with me around 10.30pm, which doesn't leave me any spare time for myself.
We are co-sleeping at the moment and I don't feel great about it mostly because I am a very unsettled sleeper and am scared that I will crash him.
I realise that it may be a separation anxiety and that children at this age go through a huge developmental changes. He is also teething and has just started attempting to stand up unaided. He has been crawling for over a month now.
What is the most difficult thing to deal with is the fact that DS just refuses to go to bed in the evening.
I am not sure whether I should stick to the bedtime routine even if it is not working or just follow his lead and let him stay late and co-sleep.
Any advice would be much appreciated :))

Separation anxiety & 8/9 month sleep regression IMO. I'd co-sleep until it passes. You could try putting him to bed earlier in case overtiredness is part of the problem (developmental stuff often messes up naps).

There is a great book explaining sleep regressions called The Wonder Weeks by two scientists who researched all the developmental spurts up to 13 months.

They say:

"Your baby may start sleeping less well. Most babies do. She may refuse to go to bed, fall asleep less easily, and wake up sooner. Some are especially hard to get to sleep during the day. Others at night. And some stay up longer both during the day and at night."

The developmental spurt causing this happens at about 37 weeks, and there?s another one at around 46 weeks.

There?s useful information about it here, here and here.

Are you bfing? If you are, there is hardly any possibility that you'll squash him. Even if you're not, at that age he should be well able to move out of the way if you were a bit restless.