M.B.
Hi A.!
The only advice I can give is, every baby is different. My daughter had no problems at all moving to her own room at like 4 months. My son is 6 months now and wont have anything to do with sleeping in his room. Even when hes asleep and I put him in there he just knows. It has to be in the pack n play in my room. And one time he wouldnt go to sleep unless he could see me laying in there too! Weird!
But I will tell you, I have noticed with both of them, once I stopped breastfeeding and switched them to formula, thats when they started sleeping through the night. I dont recommend stopping breastfeeding to get them to sleep, not that would would. But breastfed babies digest breastmilk way faster than formula and need to eat more.
But I have read that the "cry it out" method is not designed for babies under 6 months old. They dont know how to manipulate you before then, so chances are if they are crying they need something. Just my opinion. Hes probably hungry and wants to eat, and he still may be trying to catch up. Good luck!