Arguably, I'm about to sound like your mom or your (hopefully favorite) elementary school teacher, but being tired or under the weather or hungry can make you vulnerable to mental disaster.
Before you begin second-guessing everything you've done since birth, stop and ask yourself:
- Are you hungry?
- Are you tired?
- Are you stressed out?
- Are you sick?
- Might there be another extenuating circumstance — including but not limited to grief, a break-up, or an argument earlier that day — that's contributing to the way you feel?
Recently, I chose to check and write back to my emails even though it was 7:30 p.m. and I hadn't eaten since noon. Within minutes, I realized I was done as a writer; it seemed clear, based on what I was reading, that editors everywhere had determined I was a fraud.
Then I stepped back, had something to eat and drink, went for a little walk, came back to the computer and re-read my messages in a better frame of mind. I realized that they were actually super friendly and enthusiastic.
Lesson learned. Take care of yourself before you take care of work.