There are some days that it is difficult for me to concentrate too. You can hear the best music or have the best tea in the world. It doesn't matter.

 When you deal with this kind of situation, in which there is a lack of concentration such that you cannot complete the set tasks, the only thing you have to do is rest. 

Unplug your brain because whatever you have in mind to do, I can assure you that it will not come back anytime soon.