My LO started sleeping worse around 3.5 months. Since then it’s been leap after leap after teething and cold etc etc and we got into the habit of bedsharing. She naps and starts her nights in the crib and then she and I usually start cuddling around 10pm. I think we’re even getting some five hour stretches in! Crying as sleep training just isn’t for us (at least not at this point-she could cry for hours and I just don’t personally think that’s healthy!) we have her her “own” room though. Here it is