suiledonn, I could have written your post! I had PND with my first and lived in chaos. so, so draining, especially when DH came home and i had to fight feelings of guilt.
Then DS2 arrived and took all the PND away, and I suddenly got fed up of the chaos and started pushing myself to get some sort of system in place. Easier for me, though, as DS1 is at school so I have more time! But I completely empathise - some people are just Born Organised, and the rest of us just don't have brains that can think 8 years in advance or put things together in logical places (i.e., all wrapping paper/sellotape/birthday cards together, although actually I might do that now).
What I did was try Flylady. Have you heard of her/it? You'd love it, it's written for people like us. She is not born organised, she is scatty, but brought herself to order and can teach us to, too. See here I bought her book, Sink Reflections, which is very funny and VERY helpful. There are also Flylady threads on here you can join.
She taught me to do stuff at the same time every day, and when I do it , the house runs so smoothly and I'm so much less stressed.
One thing hit me from your post: the bit about sorting and re-sorting clothes for charity shops. Charity shops will take everything and if they can't sell it, they'll chop it up into scrap (for blankets) or throw it themselves. So take the entire lot there. They won't hate you - they'll be pleased.
Please get the flyLady book. It's so brilliant and she sort of gets inside your head and teaches you to think like a Born Organiser. Her mantra is "You can do anything for 15 minutes", so i'm ALWAYS setting the timer for 15 minutes and doing one room - blitzing the kitchen, etc. It's amazing, REALLY amazing how much you get done in 15 minutes. Really, really, really. I'm always surprised. Some days I just do 30 minutes' tidying/cleaning and the whole house (smallish, but not tiny) is transformed.
Please do come back and keep us informed!