It's not selfish... its the timing. You are trying to cram a list of undone things and then feeling really bad about it.
Of course you need to prioritise your health and well being. You and your whole family depends on it.
I think you should go on the hols.. as a change is truly sometimes as good as a rest and you won't be looking at the undone renovations feeling guilty. Less washing too as you only have your holiday clothes to deal with. Hopefully a few fish and chips suppers so a bit less cooking too.
The weather's great at the moment, walks and picnics, have a good internet search to see what's nearby. And write a list - or get the kids to write a list of what can be done. Get them involved in thinking about how to make the most of it and to do a day plan. It is a tiring age, but I'd let them make some choices of what they want to do and get them involved.Your DC will be much easier to manage on holiday than they will be at home.
Can you hire bikes? Or do some water sports if you are near a beach?
Another thing we did at that age was that they had holiday pocket money... so instead of constant nagging for icecream they could buy it themselves.. it is amazing how careful they were with their own cash and it saved lots of nagging and squabblin.
Tell yourself you will sort out everything on your giant To Do list when you get back.
You need to make a realistic renovations plan, allowing enough time to do things. I've got a spreadsheet... and its really satisfying to tick things off. Some jobs are much shorter than you think... some take a lot longer.
Are there any online groups that might help you that you could access whilst on holiday? Get as much tips and advice as you can... and start making a plan.
Also start using the Drink Aware app. It's really helpful in showing you how many units you are taking and where you are slipping up.
There's all sorts of soft drinks you can have, non alcoholic beers (which I think taste just the same). Stock up on those for the caravan.
I would give your DH a pass for the first day/two days if he is truly exhausted. We are always extra tired on the first day due to the run up and the travel and everyone is content to just rest. But let him know that he's getting time off but its share and share alike.. Day three will be your day. He takes over. That should give you a bit of space.
You sound tired out. Have an early night tonight if you can and try to relax. You may feel much better after that. Also another advantage of cutting back on alcohol is that you actually sleep better .(bring a sleep mask for the caravan. Its a drive to hols by the sound of it,which is much less work than going abroad.
Hope you manage this. Best of luck.