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.

http://www.sciencedirect.com/science/article/pii/S0166432812004470
http://www.sciencedirect.com/science/article/pii/S0166432813005524
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440795/
http://press.endocrine.org/doi/abs/10.1210/jc.2007-1726