I’ve been using this word incorrectly for years

[Breadyl]

I thought hysterical meant funny, very funny.

that was hysterical!

I was in hysterics (laughing)

No idea where I got this from but I use it a lot!!

That’s a common use of the word. It might not be the original meaning, but it’s so prevalent it’s become standard. I wouldn’t worry.

Informal usage means 'extremely funny'.
You are fine. No one has been commenting that you used the wrong word.

It’s a dictionary definition. Related to the idea of being so funny you can’t control your emotions.

I agree that it's commonly used in that way but it is one of those fascinating and highly sexist words that has changed meaning pretty quickly.

Oh really?!

I came across the definition the other day and was mortified!

feel better now, thanks!

it surely means both? I wouldn't think one trumps the the other? Although strangely now when I think of it I owuld use 'I was hysterical' in the bad way and 'that was hysterical' in the way of it being funny!

Words change meaning over time. The etymology is from the Greek word for womb and was applied to women . It still is sometimes used in a derogatory way but the common colloquial usage is funny.