I mean the days when you are tired, even if you eat well during the day, you are still hungry and irritated, you find it difficult to concentrate, and it is impossible to communicate with people for a long time, or even when you try to hold something in your hand, it seems to slip out.
Depression isn’t necessarily something that’s “caused”, it can just happen and someone can be 100% normal for a good long time until that “squeezed lemon” feeling builds up enough that you just shut down.