I hate the term “rock-bottom” and all of the sloppy metaphors that are associated with it.
Here is the problem: you only know where the bottom was in retrospect. When you are at your lowest point, you honestly have no idea how much further down you can go.
So that makes it nothing at all like rock bottom. If you fall in a well, you will know when you hit rock bottom. It is painfully obvious, literally.
I have been at my lowest point ever in my life, many times in my life. I have felt like I could feel no worse than I did at that moment, only to feel worse the very next day, or the next week, or not for several more months.