The following might help - I have lived a life of reboots, restarts and generally learning to get back on the horse - I also had to learn to walk from scratch three times - and each time I came back better - that's the trick
You have drawn a line in the sand by putting up this post. That's a fantastic start. A large part of the battle is realising you have a battle to fight.
You know your weakness (grumpy old man). fair enough - let's use it.
You are angry at everything - I'll assume that's because things are not the way you want and you are no fun to be around (your words) so lets use these two points constructively.
You need to take long walks, proper long walks, ( I assume your health permits) not just down to the news agent, but proper long walks - get out for an hour or so and build it from there (make sure there's a treat at the end of the walk (the half way bit actually, before you turn and head for home. use the time to clear your head and set about solving the world's problems - I do, honestly. I'm a few years younger but things are not quite how I would have them be - so I use the walking time to think things through and walking - it's solitary - you sound like you need your space
and it's a great bit of 'Me' time.
Now the clever bit.
If you set out for your first long walk and it doesn't go according to plan, the whole thing will fail.
Start with a shorter walk, but each day make a conscious decision to go that little bit further/longer and build up - see where it takes you. (My last injury took me from three years on crutches to learning to walk again and then doing the Loch Ness Marathon - objective achieved..
Keep a very basic diary - time, distance covered and for a bit of fun - list the problems you want to sort out - you can always start with Kim and Trump's pi**ing contest, or you could start off with something smaller - have fun with it.
Also - and here's the big one - you are not alone, We all have family issues to one degree or another and trust me, stress is everywhere - your's might be down to different reasons but its all there - I deal with mine by walking. I've spent 6 hours on a treadmill on a Sunday morning and on occasion, I will just get out of the passenger door in the car and just walk home - I don't care where I am. Recently, my wife has learned to stop the car so I can get out safely and sometimes I have to get out the house so quickly, I don't even stop to put anything on my feet. - so we all have stress!
I hope this helps. I hope it made you grin a bit and I hope it has given you some ideas, but mostly, that it has given you hope and ideas.
PS. in a previous sporting life I was a national level junior, my nickname was Phoenix - and trust me I came back from the ashes. Coming back from the ashes is what I do.
T2 Oct 15, met time release, diet and a daft amount of exercise