I suffered with depression on & off for most of my adult life. I thought it was "me" and in part stemmed from some fairly traumatic teenage years. It took me to the grand age of 48 to discover it was caused (mostly) by hormonal contraceptives. I say mostly as I have had a lot of trauma, and I won't dismiss the emotional fall out from that entirely, but I am by nature a fairly optomistic happy person. And I did have several periods of therapy, psychoanalysis etc which helped deal with and move on from the trauma immensely. Gaps in the depression, which I had credited to periods of super healthy living and yoga etc, were also (with hindsight) times when I was off birth control. I could only do the healthy eating/yoga etc because I wasn't depressed. When I wasn't on top of my diet and exercising, it wasn't because I was "useless, fat & lazy" but I was depressed and ground down by the side effects of birth control. Over the years I've had several types of pill, depro, mirena coil - all as bad as the other for me.
When I tried to talk to GP's etc over the years, I was offered anti-d's, no questions, nothing else talked about or considered. hormonal contraceptives not mentioned once. Turns out there are millions of women affected this way by hormonal contraceptives, and put on anti-d's as the cure for their depression with no link to birth control ever raised.
So it took me years and years to work this out. I know there are many causes for depression, but for any woman suffereing I would advise to consider the impact any medications you are taking long term might be having on you.
I'm 4 years "clean" now. And no longer fogged and undermined by a daily depression I simply couldn't find a way out of. I makes me sad and angry when I think of the impact birth control/depression had on my life for 30 years. Thankfully I'm naturally optimistic and forward looking so I've been able to put it aside and not dwell on it. Now is great!