My son is 4 months old. And he slept in a cosleeper for only the first month. After that he did really good st sleeping in his bed. Well since a few weeks ago as soon as I put him in his bed he wakes up. Or he'll wake very shortly after. Bht if I let him sleep with me he'll sleep for 4 hours at a time. Sometimes more. In his bed I get half hr tops. Im not sure what to do. Is anyone else have this issue? I thought it was thw regression but it doesnt make sense why hell sleep so long in my bed but not in his.