I didn't understood ch 37!! Can someone explain it to me in simple words please? Maybe I ...

watch the clamps you will understand then

Yes you pretty much have to read about 80% of all of CLAMP's work for you to understand at least one of them...?! Its actually a really good marketing strategy so don't be sorry dear ^^

Thank you @Mikapoe and @-_- you were right. What I did was reread xxxholic manga and I think I understand some things now.

Chpt 37 and 38 gave us a really good explanation of what is really going on. As far as I can understand, Watanuki is in another dimension where he can fufill his own wish of seeing Yuuko, what caused him to me troubled because he wasn't attendind to the customers of the shop he inherited from Yuuko, in another dimension, another time, where Yuuko is already gone (check the ending of xxxHolic for more explanation). At the same time, he's the one remaining to provide for the wishes of the real Syaoran, since Yuuko, in exchange for the price of her time, attended the wishes of the clones. Something happened between the ending of tsubasa and the ending of xxxHolic that is being still worked on and explained on those spin-offs. Need to get a good read and a great attention to the last chapters of both Tsubasa and xxxHolic (specificaly the ones where Watanuki meets Syaoran and Sakura in his dreams xD) That's quite a wide net of information, hahahaha... Hope I was somehwat useful >.>

Thank you @Lil with ch 38 now I can understand a lot!