What is this sleep regression?!

Sunni

My son is 6 months and has been a pretty good sleeper and it seems like for the past month it has been rough. Consistently having to get up and rock him and I have to end up picking him up if I ever want him to sleep, and last night it was like the moment I put him down he’d wake up and cry. Anybody else having this problem? I’ve seen some posts about leap 5 but not really sure what it entails?