Why doesn’t my son sleeeeeeep

Ok so fully admit, my son has never been a great sleeper. We did sleep training programs and did our best to be consistent with bed time routine. It worked off and on for a while. But lately...OMG. He cannot fall asleep unless I am laying with him. Since he is still in a crib, we lay in our bed. Normally, he’d fall asleep and we would transfer him to his crib, no problem. He has become so sensitive now, any movement or sound he is awake and crying. He has barely slept in his crib the last week. We put him down and he screams. If my husband picks him up, he screams. The second he sees me, he stops and goes right back to sleep...next to me. It’s a vicious cycle. And it is exhausting for all of us. I don’t know what to do. It’s easier to just bring him into bed with us and avoid the tears, but I don’t want this to become the normal thing. Help. I’m so tired. And frustrated.