I dont think my gran has dementia but I am overwhelmed with the sheer THOUGHT of all the things in the house that need taking care of and the amount things that I WANT to be doing. Bear in mind that at the moment, I am not doing much, it is the just the sheer THOUGHT of all the things I'd WANT to be doing. Is this normal and how do I come out of this potentially downward spinning spiral, and still feel as though I am well on the way to achieving my goals?
You sound sweet. Please take care of yourself, since your parents aren't likely to do it!
It is no disgrace to still be living with your parents at 22, but it certainly doesn't seem to be healthy for you. Have you considered moving out?
You describe a very dysfunctional situation. I wonder if the first step isn't to get out of it. If you lived on your own and visited Gran and invited her to visit you and took her out to lunch or whatever you'd enjoy together you would be less "helpless."
The downward spiral you describe is real and is probably more serious than Gran's impairments. You need to get help for it. Therapy can help you break that cycle. Please find a counselor.
That helps me a lot when tasks start mentally bumping into each other like little go-karts.
What needs to be done daily, what can be done weekly, monthly, etc.? But start with what absolutely needs to be done daily - start with a zero sum task list, then gradually add other tasks.
And when you feel overwhelmed, take a break and do something you love. I find music and art (colored pencil drawing) help; so does creating garden designs, planning quilts - anything artistic and creative.