Separation anxiety

We went through this! I won’t lie there’s not much you can do / that worked for us bar keeping doing it, playing peek a boo (physically stepping out of the room not just with hands) and having someone else there immediately distracting him x

Babywear?

This is so normal! This age and later they have to learn all about things being present even if they can't see them its called object permanence. As above peekaboo is good or hiding objects/toys and then them reappearing again. They'll eventually learn but its a very tough phase. Try and lean into their want/ need to be with you if you can, let the housework wait when you can and 1 on 1 time will help x

Also when they get older and have phases like this (closer to 12 months) you can tell them "mummy's coming back" and sometimes they will understand that reassurance and this might help with repetition