Everything everyone has posted is resonating with me too.
My most recent bout of therapy, there have been many, taught me one thing.
That is to do things for 1-5 mins. The wasted minutes while you wait for the kettle to boil or the microwave to ping. Do something. Anything.
Wash a few dishes. Wipe down worktops. Sweep the floor. Tidy out a drawer. Brush your teeth. Brush your hair. Wash your face. Tidy your entrance hall. Anything at all.
I've been doing this for a while now, and the wee burst of endorphins at, say, something as simple and productive as sweeping the kitchen floor is great.
I've avoided doing the same task at the same time e.g. morning kettle boil does not automatically equate to teeth being brushed, it could be tidying out a drawer.
I've extended the 'drawer tidy' to include other drawers/areas that were cluttered/untidy and, slowly but surely, I'm declutting my home. Sadly, I don't have the patience/ability to decide what to donate or what to dump. I was all for just bagging the stuff and dumping it until my cousin offered to take the bags and sort out what could be donated - she's well aware of what charity shops sell because she's a massive fan! She reckons about 20/25% of what she gets from me is dumped. The fact 75/80% goes to charity gives me another wee boost.
These are baby, baby steps but, for me, they are working.
This week I've started 'tasking' for the duration of a wash-cycle (quick wash 28mins). This means I can have a shower/wash my hair, or sweep out the entire flat. Haven't worked out which other tasks take 28mins yet!!
I hope we can all find something to help us out of this despair, because it really is a state of despair.