I want to preface my next comment by saying that a) this government is an absolute shit show and you'd need a book to list all the things they've fucked up on, and b) I don't think lockdowns are the long-term way to deal with a virus that's not going anywhere (more investment in healthcare and T&T being the bloody obvious fixes needed).
Having said that, we are where we are today. The scientific advisors are saying that the NHS is close to being overwhelmed, with huge risk to life for both Covid and non-Covid patients. The simplest way of stopping a virus spreading is to limit interaction between people as much as possible. Hence they have advised an initial lockdown of 4 weeks to try and stem the tide slightly.
It's not fun for anyone. It's going to be very hard for a lot of people. But this lockdown is a lot lighter than it was in March - schools and childcare open, support bubbles, 2 people allowed to exercise together. They've learnt at least from some massive mistakes they made in the spring, even if the rules are vague and often illogical now.
It's depressing that so many people don't seem able to think of the wider society for four weeks and then see how things are. Really depressing.
If lockdown continues long-term I'll definitely be someone assessing how it's affecting the mental health of those closest to me, and seeing what can be done to help. But FFS, is it that hard for most people (exceptional physical and mental health issues excepted) to try and limit their exposure to other people to only where it is absolutely essential, for a few weeks?