Hi, OP.
Then maybe what you need right now is to be very gentle with yourself. Give yourself lots of pampering, TLC, be very kind to yourself.
Don't think or worry about tomorrow or next. Just focus on the next hour.
When those feelings occur, do what you need to do to manage it. If it's to cry, curl in a ball, just sit and stare for sometime..whatever it is just do it. Once the feeling if panic passes, give yourself a treat. Whatever makes you feel good. A bubble bath, mindless TV binge-watching, aimless scrolling on the Internet, funny YouTube shorts videos, music...whatever it is. Give yourself permission to not be 100%. Or even 60%.
You are still in shock.
Keep hydrated, eat regularly even when you don't feel like it. Someone gave me this advice when my marriage ended. I thought it was a rubbish advice . I was surprised that it did make a difference.
If you need some time off work, ask for it. Don't feel bad about it.
Sending you strength.
You will come out the other side. 20 years is a long time, you will need time to get through the shock.