Can I get some reassurance that this is normal?

DS is just shy of 5 months. We EP with 1 bottle of formula each day. He started fighting his bottle a week ago and in the last 3 days, he's been flat refusing one or two feedings a day, wont take more than 4 ounces at a time (was eating 6-7 ounces before) and half the time stopping at 2-2.5 ounces. He was eating 30 ounces a day and now is only taking about 12-15 ounces during the day time. I can get him to take a few more ounces with a dreamfeed, but even then its 2-4 ounces. He's started waking at night too, but when I offer him a bottle he takes 4 ounces max.

He still has wet diapers, he seems pretty happy otherwise, but the lack of eating is creating bad naps and he's waking in the MOTN (last night 4 times). He's not crying when he wakes, just hollering and wimpering, so I don't know what the deal is.

He IS drooling a bit more and sticking out his tongue, but I don't see any teeth buds and he doesn't seem to be in pain.

Anyways, any advice or experiences with this? Do babies just not eat sometimes? DS did have a bottle strike of sorts in December when he was 3 months old, but it was mostly that he was fussy at the bottle and would eventually eat. And he didn't have nap or MOTN waking issues. This flat refusal, mouth-clamped closed, and spitting out milk thing is new.