DD is 4.5 months and definitely in the 4 month sleep regression. She is clearly more aware of her surroundings and I think it's making it harder for her to sleep.
She falls asleep for a cat nap after feeding at around 8 pm for about half an hour and after that she is wide awake and I think pretty much any noise or light or movement stimulates her and makes her want to play.
If it wasn't for the SIDS guidelines I would try to transfer her to her cot to see if she would sleep longer. Should we just stick it out until she is 6 months? I can't think what else to try.