Probably not as serious as some of the other posts I've seen in this subreddit, but yesterday after my shift I noticed I was feeling nauseous and flat, so I gave my boss notice that if it kept on going, I would be taking the next shift off.
To his credit, I saw that he asked if anyone could take over for me, but because he couldn't he expects me to come in.
But I will admit that I am pissed off because this is happening after I've just worked nearly triple my rostered hours when others have called out, but when its me, no one can help.