[trilinearnz]

This has happened enough that I've come to identify a pattern. For me, it's a combination of a poor environment (bad configuration of team, project or workplace) and plain-old genetics (naturally prone to anxiety/depression necessitating medication).

The former (environment) can, with time, sometimes fix itself. Not everything has to be under your control for it to improve your conditions. For example, if a particularly intensive project concludes, or if you are transferred to another team with a fresh set of people and different problems to work on. This is kind of similar to getting a night's sleep. You didn't do anything (well ok, you slept), but the next day (i.e. your environment changed) suddenly you feel a bit fresher and the things that preyed on your mind the previous day seem farther away and less intrusive.

More superficial, simple things like reducing caffeine and exercise can help, and may even solve your problem if it's not too deep. But I've found these work better as enablers for the above-mentioned two-pronged solution rather than a treatment in themselves.

Hope this helps.