Have you paid any attention to the weather when these things happen? I go through a similar reaction every time a high pressure system is moving in. I don't have thoughts of everyone being better off without me, but it comes across as what is the point of continuing when so few care.
Just like you, it's gone by morning. I think it is a reaction to the change in air pressure because it only happens with high pressure is moving in. When it is moving out I feel fine. Something to think about.