@DarkWingDuck yes. I think that sounds like Autistic burnout / shutdown.
I've had to be very strict with myself the last few years. I can no longer attend family functions, or give too much of myself, as I just am not capable. Daily life is difficult enough. I also think the different aspects of Autism and ADHD can be a nightmare as in 'competing with each other' (I have Attention Defecit ADHD and don't take meds)
I'd implore you to be kind to yourself and allow yourself time to rest. Somehow or other, your family also need to understand this explicitly. Going forward, work out what you are capable of and don't give any more than you're capable of giving and doing. (I know this is hard, as I'm a single parent and disabled myself, but I've had to be really strict with myself after suffering a near breakdown early last year)
Hope you're able to rest your brain and body for a while, and have some gentle time as that's what you need. You may need to consider work going forward - do you need time off / see a GP initially to buy some time. The most important thing right now is taking pressure off yourself.
As far as links go, I'll have a look and see what I have saved. When it happened to me, I googled 'Autistic shutdown' and just the fact that it described / confirmed what I was feeling helped me in that I didn't think I was going insane.
Only other thing I can advise is that I communicated via text or writing things down when I needed. (Have a notepad, and write out a few brief scripts like "I'm so sorry, I'm finding it difficult to talk and I'm overwhelmed, I just need some time")
I'll come back if I can find anything useful.