Actually, I think it's pretty well known that 'the wee hours,' which I would describe as 3 to 5 am, are a pretty bad time. Many suicides happen then, many night workers have bad accidents then.

It's the time when many people wake up to find the brain is set on 'criticize.' It's a time of self-recrimination, of If-only-I had... and If-only-I-hadn't...

It's often a time for the reliving of bad experiences and the rethinking of futile, angry thoughts.

My solution is to keep books handy, and I read to calm myself. A purring cat helps too.