Lol, this is hilarious. I actually did fake sick when I was in sixth grade. For a whole week. Multiple factors played in part. I had to be out several days because I broke my arm during a basketball practice. Then, I had a shit-ton of work piled onto me. And for whatever reason that particular year I was just not interested. I don't know if I felt stressed or what. 

But, I just let work pile on and then didn't do a bunch of it. Lost one of my projects somehow and it wasn't handed in. Thus, bad grades. I had never had a bad report card at any time in my life until that point. So I forged it. I was too stressed to even think about showing my parents an unsatisfactory report card. One of those things where we definitely put too much pressure on kids. But hey, I got through it. They definitely found out, and I got in trouble with my parents, etc. In the end of the day, I succeeded in the next grades. High honor roll in 7th and 8th grade. Top 12 of my class in high school, so all in all I turned out fine after that small part of my school experience. Never faked sick again after that. Just a strange year, I'm not sure how I would define how I was feeling mentally. 

Faking for work is stupid, though. But, mental health days could be needed. I like that idea as MDK pointed out. Sometimes we're going to be stressed and just need to take a day off to re-gather ourselves. People working don't get nearly enough vacation days as they should anyway.