as many have said, it’s the end of an era. You are happy and excited for your kids, but a really good chapter in your life is just done. And the quietness and very open calender drives home that point all of the time. The pandemic certainly doesn’t help.
I liked the term low level depression stated above. That was us. H probably had it worse than me, but it seemed like one of us was ways being on the edge of a meltdown (but we melted down in different ways. He is NOT a crier like me. I stood in the store crying over a stupid can of corn because I wouldn’t need to buy so much of it anymore. Sheesh) The weird part was that we got (get) along much better when it’s just us. I think we recognize the other is hurting in their own way and we have more patience with each other and try to be supportive.
Being active helps. I know that’s so hard now and it worries me a bit for us even this second time through. But last year I tried to find one new thing each month that we could do together. Sometimes it was 2 things/month, one geared for him and one for me. But most of what we did (arcades, antiquing and comicons) are off the table.
Good luck to you.