I absolutely hate seeing the judgement piled onto people who are furloughed. Presumably these people who are now furloughed are responsible, usually work and hold down a job, pay their own bills etc. They didn't choose for their employer pay them to stay at home and if they've been furloughed, their job may in jeopardy to some degree.
Presumably if they wanted a job where they worked from home, they'd have found one. Not everyone is able to work effectively from home, we all have different skills. The uncertainty of expectation is also hard for some - lots of furloughed workers aren't quite sure exactly what their employer wants from them. Lack of structure is hard. Uncertainty is awful. There's a reason lots of people talk about the impact on mental health.
I haven't read the full thread as I don't need another outpouring of nastiness and bitterness.
A bit of training, a couple of hours per day, is great and will benefit you in the long run. If your employer is expecting you to sit there for 8 hours every day, five days a week and just do online training, that's unrealistic and really hard going. It's really difficult to stay focussed and learn effectively in those circumstances so it's just counter productive. (I have friends who work for a big company who have been told this is what they have to do). If this is the case with you, I'd negotiate how long you feel you can spend focussing on training each day. If you have a better grasp of their expectations, you might feel less anxious overall.
Incidentally, I'm not defending myself. I'm self-employed, not furloughed. I'm trying to look after two SEN children, one of whom has very significant disabilities, in lockdown conditions and keep their education going while meeting daily deadlines for my work. I'm working all the hours of the day and night. I've got clients constantly chasing me. I haven't had a single day off in weeks and I'm getting barely any sleep trying to juggle everything. Even so, I still don't feel bitter in the slightest towards those who are furloughed - I think it's hard in a completely different way that some people don't quite seem to get. We're not in a competition here about who's having the hardest time during lockdown.
OP, I hope you're doing OK. I hope you don't end up losing your job. If you can, maybe write yourself a schedule for training to give you some kind of structure. That might help. I'd also tell your employer that you're finding the uncertainty around your job really stressful and it's impacting on your current mental state. Best of luck.