what does your depression feels like to you? when do you know it's coming?

Have you ever been to the ocean when there was a really strong current? You exert all of your energy, but you can barely move. Basic things like taking a shower and shaving feel overwhelming. You don't even feel sad necessarily, everything is just a blur, emotionally. Even when you are able to do productive or even critically important things it feels like there is no reason to do them.

That's how it is for me. I'm not going through that right now, but I have been like that in the past.