After almost 15 years of depression I have found a solution.
Or at least found the correct treatment for my brain.
This year I found out that I have PMDD (Premenstrual Dysphoric Disorder). I recently made the decision to use hormone treatment and now the general depression I feel throughout my cycle seems to have gone.
I feel normal again. I finally feel human again. I feel in control again. No longer sad for no particular reason.
I hope this information helps some people.
Here are some studies on the subject of reproductive hormone levels leading to depression.