I have heard some people refer to depression as "being haunted by the black dog." I don't see it like this personally, but that may have more to do with the fact that I love dogs. However, I can appreciate what I think they are trying to say by using this term. That depression can feel like a painful darkness that can be very difficult to pull yourself out of. My understanding at least.
For me, depression can hit me when I least expect it. Sometimes I can feel it coming on, but even if I do there is little warning. When it does hit, you bottom out with no motivation at all. Sleep gets all messed up, sometimes sleeping too much and other times not enough. Apetite, same thing. Overeat at times and other times not at all. There is a whole shitload of other awful stuff too, but today I have my own visibility on my mind.
For me, depression co-mingles with some of my other stuff as well. I will typically withdraw from any and all activity. I don't really want to see anyone or go anywhere or do anything and so on. I will detach from my own life and go into my own headspace. Of course, this isn't a healthy thing to do; not for me or anyone close to me. Clearly, as a transgender person this makes me mostly invisible except to those who I interact with daily. I'm not big on social media. I hate facebook. Recently I created a twitter (not calling it x) account. I don't really care for Elon Musk, but there are some good folks on there and that is encouraging to me as a trans person. They are trying to stand up to our brutal UCP government. I was inspired to see their courage and then I realized that I, too, need to stand up to them. Not only for me, but for all the people who they are hurting and it's a long list.
So moving forward I am going to work to be more visible. I am still just 4 months into transition and I still occasionally move through the world in stealth mode, but that is becoming harder and harder to do.