are you a heavy dreamer at all? I recently read that having a lot of dreams makes you feel tired mentally and affects brain chemistry. This happens to me sometimes if I oversleep and I wake up tired with a headache. It could also be mild depression, bad sleep schedule, lack of good health/exercise, no motivation, busting too much (losing energy), etc.
what I found earlier this year : Vivid Dreams cause of excessive sleepiness - Undiagnosed Symptoms - MedHelp
what I found earlier this year : Vivid Dreams cause of excessive sleepiness - Undiagnosed Symptoms - MedHelp



I'm going through the same thing. I think it is the lack of exercise and my sleeping pattern is all messed up because I used to go to school at night.
and now I just look back at them more like
had at least 3 big threads on this). Spiritual practice and meditation has helped me a lot too and I rarely go through these episodes now.