Sleep regression?

I know ‘sleep regression’ is a thing - but thought it happened around 4 months (or hopefully not at all!).

We had been getting into a good routine at night, with his first stretch of sleep lasting 4-6 hours. Now the past 2 nights he is up within the first hour and proceeds to wake up every 45 minutes to an hour throughout the night! It’s been exhausting ☹️

Anybody else have this happen? I was already sleep deprived, but this is pushing me to the edge!