Wet Vs Dry

[SaraBeth88]

Diarrhea isn't normal and probably isn't caused by the wet food -- contact your vet if it continues!

He vomited 3 times last night and had diarrhea once but then his poo went back to normal and he's fine today, eating drinking and playing and pooing, I think I overfed him yesterday and he doesn't know when to stop

 

[Gizmobius]

That's actually possible. When Gizmo was a kitten, he was a garbage disposal and would vacuum up his meals as quickly as possible and beg for more. So I'd give him more and then he'd want even more and I thought "well everybody says to feed a kitten as much as it wants" so then he'd get more. He only ever ate canned food but had diarrhea and soft stool for the first year of his life because of that.

It's completely possible your kitty got way too much way too fast and it went right through him. I'd suggest smaller more frequent meals.