It is difficult, but I think feeling that way (that a client is just a click away!) is kind of testament to the fact that you need a break and to focus on other things! As you know yourself because you posted 

I know it's hard but I think you need to make the decision to have a 2 week break and stick to it. Work will still be there when you come back. Take actions that mean you can't go back on your word to yourself - write on your adverts and profiles that you'll be away from X date to Y date. Then turn off your work phone and put it in a drawer. The first 2 days are hard because your brain is still work-wired but after that you'll wonder why you waited so long to give yourself that much needed rest. Because this is why you work, right?  Not to drive yourself into the ground but to have the funds to take time off and enjoy life. And if anything clients will be more keen when you come back because they'll have been wondering where you are - your absence will create interest.

It really is a lovely feeling when you take a good amount of time off and get into "holiday mode" - which takes a couple of days. You deserve that,  take your two weeks and enjoy it x

I do the two-draw-shuffle. Phone in one drawer, battery in another preferably spread in different locations.
Or every now and then I do a residential bootcamp in the bush for a week. The work phone stays at home.