I guess bad days are part of the territory, I've found two things that have helped, the first is the knowledge I've managed to get through them umpteen times before, and the other is planning.
By that I do not mean anything particularly grand or difficult. for instance when good I've been reading a book and enjoying it, looking forward to the next chapter (or even the next book if they are a series). I'll then stop and put it away and start reading something else. I know it is there and when I'm starting to feel overwhelmed and hopeless picking up that book helps.
Hopefully that makes some sort of sense. I'm not suggesting books would be your answer, though as we mentioned before there are those similar to Eddings, it might be computer game instead or something else entirely. Just to know you have a something to fall back on.
Mothers, or anyone else making "suggestions" has really been a pain, often leaving me resentful and cross. First because it highlights the difference between them and me -they do not have a clue what has been in my head, and secondly they charge ahead arrogantly spouting something completely inappropriate without thought -maybe I'm just grumpy - but I suspect it is just to make them feel better.
I think your attitude to your mother is really the only possible one.
Feeling down the next day after a session is also pretty common, you are in a hopeful environment and more seems possible. The next day reality closes back in and it is hard to remember that the things in the session are still possible and still true.
As for me -ta for asking, I'm OK, last month was not good, however I slackened off my activities in response and got more rest and reading, I think it helped.