Hi,
My son is 5 & was also diagnosed w SPD & high anxiety at 4. I don't have advice, but can relate to what you're going thru. Right now he argues every decision & is hard to get listening or moving on a different thought or idea. He's five, so I can still pull rank, but I worry about how much harder it will be as he gets older. He's pretty much the same at school as at home right now. From what ive read, kids w SPD can learn to hold it together but let it out at home. I know my son is worse for us than anywhere else. Many family members didn't believe their was anything wrong. We were very blessed to have a counselor who has great experience w SPD kids & was able to teach us how to handle him & discipline him. My suggestion is to see if u can find a counselor who can teach you how to interact w her at home. It's like a parenting class but ur learning how to parent a child who deals w extraordinary stress w everyday things. We were blessed to be given "hands on" instructions. It's still hard but it helps. I know this wasn't what u were looking for but I hope it comforts u a little to know someone else is in the same boat & understands what ur talking about. I will keep u & ur family in prayer.