I bring your attention again to this Twitter thread by Connie Rourke:

I'm starting a thread of every coping mechanism I've used in the last 20 years as an immunocompromised person who lives like a(n almost-completely) shut-in.

and this Dreamwidth post by alias-sqbr:

A bunch of you are dealing with being stuck in your houses, which is something I have a lot of experience with, if not in quite the same way. So I thought I might as well give what advice I have to give.

It's amazing how much novelty is helping me. I played a fun in-browser computer game -- for those 90 minutes I was immersed in another world. I found a teensy super-old packet of decaf coffee and now a scent I don't usually smell at home wafts from a warm mug nearby. A face mask (edited later to explain: the goopy kind that you spread on your skin and peel off later), a pair of socks on feet that usually go bare, different scented lotions....