ds 9 months used to go straight to sleep when we put him down. Almost overnight he stopped this. For the last week he will lie awake in the cot for 40 mins before falling asleep. He doesn’t usually cry at all, if he begins to cry I go in, hold him for a minute or so, he’s fine, then back to lounging round awake in the cot? He’s not going to bed too early or anything like that. No reason why he wouldn’t be tired either. Is it ok to get on with the evening? First time mum and worried.