Sleep Help

My 6 months old needs to be out of my bed. He will sleep on his own in his crib from 7-12ish, and then wakes up to eat, and won't let himself be put back. So I bedshare from 1ish til morning. But when he's in my bed he chases me around, rolling into me, then pushing me away to get space. So I'm carefully balancing myself on the edges of my bed half the night, moving every half hour or so.

I've decided to sleep train. My son won't take a pacifier, and I can't use a labor intensive sleep training method because I have a 3 year old too. Last night I was the first night of a kind of cry it out method. Well he was fine until 4:30. Then he was inconsolable. I rocked him, sang to him, changed him, left him alone, talked from across the room, patted him on the back, everything I could think of other than nursing, and he just screamed for 3 hours. Nothing I did helped him even a little. At 7, when the night was over, I gave him his 'morning' feed, and he perked right up and is happily crawling around. I am at a loss. I know this is day one, but I couldn't see any cues for what I needed to do to help him sleep! Do I just stick it out? I don't know if I can listen to him scream for hours again for who knows how many nights. But we both need to break this bad sleep habit we've got going on.

He feeds at 6pm, and last night I fed him at 2:30am and then 7am.

Does anyone have any advice?