I know what you mean.

My adjustment has been that I can do only one 'activity' per day -- and depending on the one I pick, it can mean the next day I can not do much of anything. (And I do not work outside the home like you do.)

Example: Saturday - - long walk, beautiful day (but about 1/3 the distance I used to do)
Sunday - - 9 holes of golf (used to play at least 18)
Monday - - scrubbed kitchen floor (in stages! took me all day)
Tuesday - - no wind for my sails...flopped about all day waiting for energy
Wednesday - grocery shopping was the effort du jour

There was a time when all of the above could be knocked out in one, long busy day. Yes, some of it is age - - tho most of it is MG. And yet, I am greatful I can do what I can do. But sometimes fear .... well let's not go there.