I can certainly relate to the idea of an "invisible illness" as somebody who suffers from social anxiety and depression. It's extremely hard to explain to friends and family when I can't participate in various events. I'd add to that graphic the kinds of things I've grown weary of hearing...

"Everybody feels like that sometimes."
"Nobody likes doing that."
"You just have to push past it."

I'm reminded of that famous quote, "Be kind, for everyone you meet is fighting a hard battle."

Good luck with yours.