day naps for 3 months old

[daluze]

So far we've been blessed with our 3 months old DS2 sleeping through the night from ~8 weeks. So appologies to anyone who sees this post doing 4th night feed at 4am - I know how you feel, my DS1 never slept more than 2-3 hours and I didn't know it was even possible for EBF baby.
However, for the last week, I cannot get DS2 to nap during the day. He sometimes drops of in a sling, but not so easily as before and only fast walking outside. I tried various slings - stretchy wrap, which he used to love, but not so much anymore, beco, connecta and others from sling library. Or in a moving pram outside. But at home he would only nap in the dark bedroom being held - if I put him into his cot, where he happily sleeps at night, he wakes up and cries almost immediately.
I had similar with my older boy, and ended up coslepping for naps until this phase passed when he was 11 months. But I cannot do this now when a toddler is at home. So DS2 ends up overtired and screaming by the evening, sometimes with as little as an hour of total sleep durong the day.
At night he usually sleeps from 8-9pm till 8-9am, with a dreamfeed ~11pm when I go to bed, and a mornong feed ~6am, which he wakes for, but goes back to sleep after. So overall, it would be not a huge issue, but he gets so tired and upset in the evenings, that it is clear that he needs more sleep at daytime.
I feed to sleep both at night and day, and try to do the same things before the naps as beforw the night sleep (dark room, etc), it just doesn't work at daytime for some reason.
Anyone gone through similar and what did you do? Especially with a toddler around. Many thanks!