I am becomming quite worried about my health. I can be fine one minute and the next I suddenly slump into a deep pit of extreme tiredness .... as if I hadn't slept for weeks. My eyes go red and watery, I start yawning constantly, my mind goes blank ... all for seemingly no reason and then as suddenly as it came on, it can go off again within half an hour or so and I'll be fine again.
Ironically, the overwhelming urge to just lie down and go to sleep all of a sudden often comes on after a cup of coffee. (but at other, random times too).
I have problems with mood swings in the same style. One minute happy and joking/next minute deep unexplained anger and feelings of depression.
What could be causing this??