How does sleep regression manifest? We haven't slept normally for two…

How does sleep regression manifest? We haven't slept normally for two days now, and it's almost impossible to put him down during the day because he wakes up every 30 minutes to an hour. Nightmares have disappeared completely, he sleeps for 6 hours in the second night, but now he wakes up every 30 minutes - 1 hour, cries, gives him a pacifier and shakes him quickly, then he falls asleep. We recently gave him vaccinations, but they said that they can't possibly affect him like that (tetanus, whooping cough and diphtheria) + rotavirus was also given.