There is a cause

Since it's the summer, I started an experiment about a month ago to test the hypothesis that lack of sleep was at least partially to cause for my anxiety and depression. I got the idea that it might last year when I was out of work and decided I would sleep as much as I wanted to, and I felt better during the winter than I normally do.

For the experiment I purposely kept myself short on sleep, going to bed later and getting up earlier. It took a month and the anxiety came back, finally giving me what would have been a panic attack except that I saw it coming and averted it with a Xanax as I was at work and had work that needed to get done that day (or it would have been a big hassle to reschedule and caused more anxiety). A good night's sleep and the anxiety went down. It stayed high for the next few days as I kept going to bed early in order to catch up on sleep.

So the experiment confirmed that lack of sleep is at least a contributing factor for my anxiety. Something to watch for. Also I need to make sure I get good quality sleep, not going to bed with stuff on my mind for instance.