JPT68,
I'm sorry to hear of the cancer confirmation, but happy to hear you are at MDA. I don't know if there is anything I can say that is helpful, but for myself, I took one day at a time, even each day was gauged from meal to meal at times, listened to music, set small goals some of which seemed silly, trivial, ordinary, but meant a lot to me or just stared at the ceiling as I was bed confined for a year. Maybe speaking with a counselor is helpful. I had one in the nursing home, I thought was free, until I was billed, but talking with someone does help, and ACS, other organizations as well, pair you up with a sponsor that went through something similar to speak with, if that is possible, and discussing anything here as you noted. There are also monthly SPOHNC meetings at various locations in the U.S., and wouldn't doubt MDA has one or their own HNC support group.
I've been down the road where I have trouble getting out of bed, don't want to do anything, even to this date, and if wasn't for my doctor visits I wouldn't, but I have to admit you should do some type of activity, like light walking, if approved and as advised by your doctors, and be in shape for surgery, which helps in recovery, and survivorship/QOL as they now term. They may suggest PT somewhere down the line, even before surgery, and recommend that too.
Best wishes, and thank you for updating your post.