The desire to take a few days off is only natural. Your mind and body will adjust to just about anything you subject it to, so whether you work 14-hour days or are unemployed, that is your status quo, and you're both accustomed to it and need a break from it. Then again, if you work a lot and start taking a lot of days off, that status quo will decrease to a level where you work less - and you'll get used to it and will want a break from it. (It also works the other way around: if you try working a little more, you'll get used to that and feel like you should be working more.)
It's a vicious circle.
But hey, there's a solution! Instead of giving into your desire to have a little holiday immediately, you set a date - at least a fortnight ahead - and write down everything you need to do before that in order to deserve the holiday. Make sure the amount of work or tasks or projects you need to complete before the deadline is more than what you would usually do. Like, a lot more. Double or triple even.
This ensures, quite conveniently, that your status quo isn't shattered by the holiday - because the amount of extra work you've done before the holiday and the holiday itself cancel each other out. When you've had your holiday and return to work, you might get a slight decrease in your productivity - but it's compared to the level just before the holiday when you were triple-grinding your butt off, so it's okay. You'll be functioning on your long-term status quo level again, and who knows, maybe it'll feel like a breeze!
Having overworked for the two weeks leading to the holiday, you'll feel like you've earned it and are allowed to relax. Because you are. After all, if you've doubled or tripled your workload, you've literally done all the work you would otherwise be doing during the holiday, in advance. (Unless you're taking a really long holiday, that is.)