This shows you're already being crushed by his behaviour. You don't consider yourself equal to others, even though you are, like we all are. You think the behaviour isn't something that someone else should put up with, yet for some reason you consider yourself to be an exception who should tolerate it? Whatever the cause, his behaviour has to stop. If it doesn't, you have to leave. It's that or be destroyed.
I have suggested counselling but he refuses
Then you have your answer. He doesn't think your relationship is worth spending time and money on to improve it. He'd rather spend his time and money doing anything else. He also, with his refusal, is telling you he doesn't care if you're unhappy. That's not the mark of a good partner or a compassionate human.
We’ve been through several patches like this over the years and I always say “this one will be the last” but it never is.
Look up the cycle of abuse. This sounds like it.
When things are good, they’re great, but when they’re not I feel so anxious that I can’t even think straight.
This is signs of emotional abuse. You're responding in the way an abuse victim would. This will also be having an impact on your physical health. You have to put your own health first in life, that's not a luxury it's a necessity, especially if you have DC.
I wish he would just tell me when he’s feeling overwhelmed so that we can come up with a plan together, rather than pretending everything is fine and being angry with me for taking him at his word or trying to make plans by myself and inevitably getting things all wrong.
For whatever reason, he's setting you up to fail. He's choosing not to communicate with you.
What you're effectively saying is "I wish he would...be someone else".
If this isn't some blip for a fixable reason (and it isn't, if he won't take steps to address it or even admit there's any issues), then this is him. This is who he is and you're saying you don't like him.
Not liking someone is enough reason to leave them. It's a very good one, in fact.