Welcome to the forum DJRDIESEL!
I feel for you so very much. It's a horrible feeling when all of a sudden you find depression threatening to creep back in. Like you, I invested in self-education/understanding so as to grasp the complexities of depression and the human brain. Bit like a rabbit hole; once you begin looking into how you tick you realise there's more and more to research. We are definitely complex beings.
Depression left me alone about 13 years ago and in recent times threatened to return. You recognise it, hey, all those signs and you can be thinking 'Oh, please, not again. I don't know if I can go through this again'. Myself, I ended up going to see a kind of life/spiritual coach. I'm a spiritual (non religious) gal. Whatever works. This made a massive difference, what I regard as a 'tune-up'. Revisiting help/guidance is definitely worth considering, as our old destructive beliefs can tend to creep back in here and there without us realising, until they present as a problem.
Being analytical is not a bad thing, if done constructively. Being analytical myself, I find this mindset powerful enough to keep me out of depression. Whenever I find myself feeling challenged by my thoughts and emotions, I ask myself 'What am I being challenged to change regarding my beliefs/perception?' Of course, it's not simple. Changing my beliefs means changing my identity in some way (how I identify myself, in relation to the rest of the world, including the people in it). Eg: Because I'm someone who rarely proclaims 'I love you' to those I'm close to, I've been accused of being 'cold'. This left me feeling like there's something 'wrong' with me. I accepted the challenge these labels presented to me (cold and wrong). I developed my own definition of love in my analytical process. Self-love: To be invested in my own evolution. Love for another: To be invested in their evolution. I am deeply invested in so many ways, in both areas, therefor I am loving and there is nothing wrong with me or how I express love. I just do it differently. Those who accept me know, without a doubt, they are deeply loved by me. Compromise (expressing a common promise/mutual agreement) means there are times when I will say 'I love you'. I identify as someone loving who compromises.
DJRDIESEL, you are in no way 'broken', just facing incredible challenge. Changing our identity in constructive ways is a skillful art, an art of self-understanding which offers many rewards.