Never Sleeps at 14 Weeks 😭

My son is 14 weeks old, and he is a horrible sleeper. He never used to be but for the last 5 weeks, he only sleeps for an hour at a time at night, with hour long breaks in between and naps twice during the day for 30 minutes. He gets a total of 7 hours (if that) every day. He wakes up at night always hungry, so we tried pablum last night and it worked! He slept from 9 till 3, had a bit more and fell asleep again till 7I was so happy, but today he completely refused it. He was literally screaming for a full hour after bedtime and wouldn't relax until I have him regular formula with nothing extra. Idk why he won't take it all of a sudden!

- he isn't gassy, I know when he is and it's not that

-it didn't upset his stomach (again, I know when it's upset)

- he's not constipated - he popped just like normal

-the nipple opening is big enough - I tested

- we never changed his formula

- he has a solid bedtime routine that includes a hot bath and a soothing rubdown after

I've tried literally everything and nothing works, he just refuses it all of a sudden. But, without the pablum, he's back to his horrible sleeping pattern. My husband is never home, and I have no support at all so idk what to do. I'm lucky if I get 3 hours of sleep a day, so I'm starting to become very sick and depressed. Someone pelase help, what can I do to get him to sleep more if he won't even take the pablum?!