I've got "it". When I was teaching I always started out spring break with what I called the Vague Virus. I'm sick but not too sick. Everything just feels off. I don't want to eat. My tummy feels yucky and so does my head. All I want to do is to sleep and lay on the couch.
That's not a terrible way to spend the day and since I don't have to use up my sick leave to do it, I don't feel a bit guilty. I'm spending the day listening to audiobooks and making great gains on the Galliano vest.
The only thing that tempts me when I feel like this is either yogurt-which I NEVER eat when I am well as it makes me sick-or something with some octane.
Then there is matzo ball soup. It will certainly cure what ails you. Doctor's orders.