@Anne65 thank you so much for your support and advice, which I will follow for sure (didn't think about preparing meals next week to have them ready when I get back home after surgery, thank you for reminding me).
I'm really trying hard to concentrate on the here and now.
Unfortunately I have grown up in a family devastated by cancer (not BC) and I think that I've been really traumatised by it, never been really able to elaborate the trauma (tried with counseling but had to be medicated with a proper therapy for anxiety and PTSD).
I have lived in fear of what is happening now for my entire adult life.
This is why I don't succeed in taking one step at the time trying to stay focused just on the next step. I have seen too much and I fear what expects me in the whole process (if I am lucky enough to see the end of it :( ).
Sorry for being so negative, maybe if i had had a different background it would be easier to cope with this terrible moments.