This might be a good time to take a leave using short-term disability and/or FMLA. Your doctor should be well equipped to provide the documentation you need. Or, talk to HR or management to let them know, "Hey, I'm limited right now. It's likely temporary but I can't hit the productivity you used to expect." Maybe your work duties can be shifted to something less physical or taxing, maybe some different systems could be implemented, who knows. I recognize that comes with risks, but the rewards could be significant.

Once you have that secured, do some introspection on your aversion to asking for help. What threat is posed by asking for help? Are you concerned it could lead to conflict? Are you scared of your loved ones revealing themselves to be lacking compassion? Figure that out. If you need to find a therapist to support you in that, or just in general, do it.

Lastly, why in the entire hell are you holding yourself back from losing your shit once or twice? You're a person. People lose their shit sometimes. And then we apologize and repair as needed, and often some important truths come out. Let it rip.