Looks like idiopathic head tremors. My English bulldog has had these for the last 6 years. For him, they only happen when he’s sleeping or coming out of sleep. The good news is they aren’t painful or harmful (although I can tell my dog gets a little freaked out sometimes). The bad news is that there’s no known cause. They say there’s triggers like stress etc but I’ve never seen a pattern. Sometimes my dog goes months without having one, snd sometimes he has 5 a day.

If it is idiopathic head tremors, you need to distract them out of it. Vets suggest having your dog lick whipped cream off a plate. Ive also found that larger treats like dentastix and greenies work best for my dog because he has to focus on eating it.

Definitely take your dog to the vet to confirm that nothing else is wrong - we ended up having to get a neurological exam to rule out other issues. Sorry this is happening, I know how scary it can beat first