It's been interesting for sure.
I started working from home mid-March and it's been a struggle. The facility I work in was already on the downward run as it is planned to close this year so actual work to do each day was already drying up end of last year. I'm a reliability engineer so as much as I do a lot paperwork to keep QA and compliance happy I do still need to go on plant and look at equipment from time to time. All the day to day stuff dried up completely though as my boss was on site and just took over everything. This left me out of the loop and feeling pretty useless overall. Sounds like a first world problem but it means I was only really generating about 2 hours work in an 8 hour day with the rest of the time spent browsing the net and watching netflix/youtube. Some days I'd get so bored I'd just throw the laptop on the bedroom floor on full volume and have a nap, knowing any messages or phone calls would wake me up. At one point I even spent a week digging up my garden and re-turfing it all with the laptop sitting on the patio...
I then started returning on the odd occasion (roughly two days on average over a 2 week period) but it didn't really make anything feel much better, or at least up until a few weeks ago. Then I went back full time to complete a decommissioning project I was working on which was nice, but I felt mentally slow. Like my inactivity for months on end had caused my brain to rot a bit. At least I felt a bit more useful though. That projects finished now and I've since moved into a new department that isn't closing down. I was meant to be made redundant in July, then end of September, but have since signed on for a 2 year temporary assignment. The getting ready to leave and then having a bait and switch thrown at me several time hasn't helped things. That aside though, I started in the new department and this has further highlighted my lack of "match fitness" so to speak so mentally I'm feeling pretty shitty about it. It also means I will predominantly go back to working from home most days a week which is a bit of a downer as I thrive off the office banter/sharing of knowledge and ideas. I also don't know most of the people or the equipment in the new department so it's like starting from scratch. It's also very hard to keep up to speed when you aren't physically there overhearing various bits of information. A big part of me wishes I just left in July so I don't have to think about it (I still have the option of leaving up until the end of September but the job market isn't great for engineers in and around Brighton/Worthing).
The only plus side to all of it is that me and the fiance have been absolutely fine (she has also been working from home since the end of March). I hear a lot of talk of couples getting into arguments because they aren't used to spending so much time together, but its not been a problem at all. More because she has the patient of a saint than us being some ideal couple though. It does mean come dinner time we have absolutely f*ck all to talk about though as EVERYTHING has been said during the day and nothing interesting has possibly happened because neither of us have left the house.
EDIT - I've also noticed that all notion of "bed time" has gone out the window. Will regularly stay up to 2-3am, as evidenced by the timing of this post, knowing full well being tired at work really doesn't matter anymore as no one can tell.