Do you have to have a reason to not be feeling 100%? Do you have to have a reason to be tired of work? To feel like you're doing all these different things, and doing none of them particularly well? To feel like you've missed something? To feel like you seem to get on everyone's nerves? To feel like no one understands you? To feel like the things you say and do are misinterpreted? To know you don't seem to fit in anywhere anymore?
I feel so sad right this minute. I'm sure I'll feel better in the morning.