I was out on SSI for a couple years many years ago and my docs put down clinical depression, which was true. Of course, I didn't know for sure I had DID, so that made sense. Major depression should definitely be safe. It's recognized as a debilitating illness and I'm guessing it should be the primary diagnosis. There are a lot of people with DID who are perfectly functional, or who might be out of commission for short periods of time interwoven with general productivity. There are plenty of people for whom DID is extremely debilitating, of course.
For you, DID may be the primary condition, the likely cause of the depression and anxiety, but it seems it's the latter combination that is causing you to need to be on disability, not the DID.
As for your current reality, many of us have been there and you'll get through it. It just may take a period of time and SSI seems like a good option. I "used" the system years ago but I'm sure paying my fair share back in taxes at the moment.
Also, Joy, I like how you phrased that. Saying you got knocked on your butt suggests that you already know that it's temporary and at some point you're going to be able to stand back up on your own again.
John(ny) academic, Sphinx gatekeeper, Marc 46 noble
Aaron 44 logger, Jonathan 33 suit, Nigel 21 reader
Quato 19 rebel, Dan 15 jock, Faolán 14 detacher
Jack 11 hillbilly, Ty 10 Brit, Brody 9 AllAm
Luke 8 farmboy, Chase 7 rich, Carter 6 softheart, Greg 6 sad
Inky 5 jumble, Johann, Hansel 4 twins, Max 3½ freeze
Little John 3 quiet, Ashár 2 wolfdog, Henry 2 lost
Edward 1½ knight, Zeb 1 baby, Adam 8mo core