She sounds so much like my dd!! We are still in the midst of figuring out what works for her. It seems age 7 the magic age for testing various things, so far she has been through CAPD, SI and will be headed for behavioral Optometry this month!
I also am SAHM and our environment is quiet and predictable in routine. WHen things are overstimulating, she would melt down or retreat.
Christmas at age 3, she came down the stairs, looked around and headed back upstairs and laid on her bed under her secuity blanket! We did a little bit all day long.
We took her to disney world, she had to go back to the Condo and sit in her bedroom. She talked to her animals and when she was ready she came out and was quite ready to go for more.
She also needs to go to her room and be alone after a full rich day at school as well. She has a walk in closet with a window (so lots of light) where she lines up her animals and talks to them until she feels like she can rejoin the resot of the world.
It has gotten better over the last few years and she has learned how to manage herself pretty well. Good Luck!
