Dear T and/or pdoc

I was thinking. I don't get why I'm so depressed. I can understand why I'm depressed, but I don't get why it's so bad. The things that we think that caused my depression, those already were there 3 years ago and 5 years ago and 7 years ago. Sure, during those years more things have happened. And I've felt depressed several times during those years. But it was never this bad. Not even close.
Why is my depression now so severe? And why has it been like this for more than 1,5 years? I feel like I don't have any reason to feel this bad.