I am at a loss

We finally made it over the 6 month hump of no sleep & no we’re on to a new struggle. He has never had a problem falling asleep on his own. Saturday night we put him down at 7:30 (trying a new bedtime) and he slept through until 6 a.m. This was huge and we thought funny we’ve figured it all out. Well, last night we put him down again and he was screaming bloody murder like somebody was hurting him. It was a scream/ cry we had never heard before. We kept trying to console him and nothing worked. Finally we caved and let him in bed with us. He slept get for 3 hours but then was up fussing again. We tried putting him in his own crib and again he was doing that scream/ cry. I tried rocking him and nothing was helping. I finally just fed him a bottle (which he chugged) and I tried to put him down in his crib. He immediately started to scream so I figured I would just rock him. I rocked him to sleep after an hour & he slept from 3:00-7:00.

We put him down for 7:30 tonight and he was doing the scream again. I picked him up once and put him down and he lost his mind again. After a few minutes he calmed down & he just fell asleep on his own. What could be causing this? Our night routine hasn’t changed with the exception of starting it earlier. I feel so bad hearing him cry like that but we are both working parents and these past two months have been so tiring 🙈😭