I think you are being exceptionally hard on yourself.
You are not the only one - but it is the way I work :)
I like to have the Is and Ts dotted and crossed, but I don't like dotting and crossing! :D I am more of a "wing it" personality, but have to take more care and responsibility to get things correct, which is probably the "stress" cause.
And you are right, the kitchen actually is a timeline issue. I was meant to have an extra two weeks of holiday off to prep for it, but was forced to return to work instead, which means renovating at the same time. Had I had those weeks of (as planned and denied by my boss), I would have been able to do all the prep on holiday :)
I'm sorry that you didn't get the time off, that seems like a bit of a dick move by your boss and he clearly isn't doing you any favours.
Winging it with some things works well and sometimes one needs a more structured approach, I personally think that you are being hard on yourself because you had expectations of it being different had your holiday panned out correctly. It sucks when things get jumbled, but the kitchen will get sorted, it will just take time. Don't lose heart, imagine how awesome it's going to be once it's done!