What is happening?!

Lincoln is 19 weeks. I thought we passed the four month sleep regression and Lincoln went back to sleeping 7pm-4amish (eating ) and then back to sleep til 7. That lasted maybe a few nights and now he’s back awake every 2ish hours and he wants to eat 2-3x a night!!! And he takes anywhere from 3-5 naps a day depending on length. Most naps are only 20 minutes.

I’m literally going insane. He only naps short spits and then I try to keep him awake 75-90minutes and he’s fussy most of the time because of the short naps.

He puts himself to sleep for naps and at night and I do “sitback” when he wakes to try and get him to self soothe but it doesn’t work. I don’t want to sleep train until 6 months but I’m at my wits end. Help!