3 year old sleep trouble

My son has slept in his own bed and through the night since he was 9 months old. He is now 3 and for the last week he has not wanted to sleep in his bed. He screams for hours before he finally goes to sleep. I have had to lay in bed with him or take him in our bed for him to finally go to sleep. Then, he wakes 2 more times throughout the night and if I’m not there he cries and screams for me until I lay with him again.

Any suggestions on how to deal with this?