No, dear, don't think of your self as untreatable. it took years to find a combination that worked for me, and that may have been possible after a new version of an old drug came on the market. After all, you stopped yourself from actually hurting yourself and journaled it. Something is working, just maybe not fast enough.
Special needs kids are hard to deal with, no matter how sweet or happy or clever they are. We are, I think, hardwired to expect them to achieve certain milestones at certain times, and our instinctive response when they don't is impatience and iritation. If these emotions trigger you, then it is very difficult.
Have you told hubby how you are feeling? Can you ask him to handle the kitchen for you until you feel safer? I'm less afraid of you hurting yourself because of being down and more so out of impluse right now. Huggs, and I wish I could come and distract you, I don't know, by dancing like my cat or something.