I think many people have experienced the 'Covid blues' this year, I certainly felt a bit down and grumpy during the first lockdown, with the change in pace of life. I used to work a job travelling 1,000 miles a week all over the UK and Ireland, working 12 hour shifts outdoors commissioning substations. Loved it - very demanding and a great consumer of time and energy, but very rewarding also. Did that for nigh on 15 years. Left that job last September, reluctantly, because of family demands, and took up a position locally doing an office based role in the same discipline for 60% of the salary, so was home every night on fixed hours, but the job itself is immensely tedious and soul destroying. I accepted it as a necessary evil, and threw myself into classic car projects and recreational drinking. Come the Covid pandemic, we were all told to work from home (not furloughed thankfully) for the foreseeable future, and nine months later I am still here. Really struggled at the beginning - in the space of six months I had gone from being an independent free spirit, to effectively being under 24/7 house arrest.
Excavated all my home brew equipment back in May after a few years of not brewing at all, some of the grains were actually still viable, so brewed a beer to lift my spirits. Been brewing on a regular basis since then, and now have three corny kegs and a keezer - I was drinking waaaay too much over the summer, probably 20-30 pints a week, drinking every night and putting on weight. Have cut down now to 5-6 pints a week, which seems much more sustainable. The cold weather has somewhat curtailed my outdoor classic car activities, so that's a challenge, and there are days when I'm immensely irritable for no apparent reason. My wife has asked during a tense exchange of views "are you depressed or something?", to which I had no immediate answer, but had me thinking. I don't believe to be irritable and short tempered is necessarily to be depressed, but it's certainly been a strange 18 months. I pride myself as a Grumpy Old(ish) Man, so don't consider irascibility to be particularly out of character.
We keep chickens as well, and for the last six weeks one of them has been indoors as she was very thin and underweight, so have been nurturing her back to health. She seems to have grown a strong attachment to me, and every evening paces up and down the kitchen at around 9pm, protesting mightily. It took us a few days to figure out what was wrong with her, but it soon became apparent she wanted to take up position on my knee on the sofa, and have a little snooze. I sit down, she comes running over, jumps up and makes herself comfortable. I've found this surprisingly therapeutic - we have had chickens in the house before to take care of them and nurse them to health, but never one who has formed such an affectionate attachment, or demanded attention in this way. She's a very sweet little character, and I'm very reluctant to send her back outside now she's back to full health.
One other thing I did last year that others have mentioned - I used to be a complete news hound, listened to all the news bulletins on Radio 4, watched evening news on BBC, read papers online, listened to podcasts about politics, etc. Stopped all that completely. The incessant and relentless influx of bad news and bitter conflict eats into your soul and gets you down, I felt much better when I simply stopped entirely. I speak several times a week with an old friend at the other end of the country, and he is utterly consumed by the news cycle - every conversation starts with "did you see on the news (insert terrible happening here)?" to which I reply "I don't watch the news". Same story with social media - Faceache is another depressant and time waster, more or less stopped using that now. Politics in this country has turned more toxic than any time in my living memory, and I say that as someone who grew up in the bad old days in Northern Ireland, and now live in Scotland, where political conflict seems to be in the water. Depressing and corrosive.
To the OP - you have highlighted something a great many people feel, and it's right to express and acknowledge it.