If your MS is anything like mine (and let’s face it, it probably isn’t but…) i don’t think it is an ‘either… or’ situation; My MS symptoms can be provoked BY stress and so what you might have, is a bit of both.
Life can provide us with a wealth of things to spend time and energy worrying about. Several of these things are beyond our control, but there are also many others which can be controlled, if only procrastination wasn’t a more accessible alternative.
Your house is a mess and so is mine. I don’t care and thus wouldn’t ever mention such in a post like this. You however, did mention it and so i might suggest you work to get on top of it. Not because it needs to be done, but because it would make you feel better once it is done.
Fatigue can be a problem of course, so set yourself out to do a little, but often. Your current disinterest is possibly due to a sense of the challenges being unsurmountable.
I suspect that you know what you need to do to feel better about your current situation. You just need to find the mental frame of mind that will allow you to put the necessary processes into action.