Hi Tom,
This state of yours, did it last for long time is it recent?
There are two things which came to my mind when I read your post.
Could it be exhaustion? Physical or mental. Lack of sleep? It can happen that our body sends us a signal of alarm saying “I cannot take it anymore”. Could also be a hormonal unbalance also which you cannot improve just with the power of spirit. On the other hand, according to many research, proper life hygiene can be very helpful: healthy regular eating, moderate exercise and enough sleep. If it doesn’t improve after these measures have been taken, I would discuss it with my family doctor.
Another thing is more on the psychology side. I read an article describing the research findings that sometimes the so called positive psychology can give a bad result. In other words, when we force ourselves to feel good, it produces the opposite result. Maybe if you let yourself experience the negative emotions without fighting them, but without nurturing them either, they will have less power over you.