Sleeping nightmare all the sudden 😩

Please tell me I’m not alone! My 18 month old has been a great sleeper and the last two weeks he won’t go to bed. He just cries and cries to the point he’s throwing up. So now I’m at the point I am afraid to let him cry to long because I feel like he’s going to make himself sick but I don’t want to lose/ruin all the work we’ve put in of him being able to go to bed on his own. Making me want to rip my hair out.

Let me also add that now when he wakes up in the morning early or even during naps he can’t get himself back to sleep anymore unless I go in the room and stand there until he falls back asleep. It’s like he’s afraid of something all the sudden.