Hi Me2.
I don't know who told you that you had to be relaxed and calm. You'd need to be superhuman to achieve that! There's no living human that ever received a cancer diagnosis without feeling like the earth had opened up beneath them. I am so sorry for your diagnosis and hope it all goes well with your appointment.
My best advice is to just take it one day at a time. I'm now just a few months off four years since diagnosis and I can still remember very clearly the shock I was in when I was first diagnosed.
I found it very helpful to repeat the phrase 'It is what it is' during those early days. A fellow survivor encouraged me to say a word starting with 'f' (forbidden on this site) very loudly and repeatedly and I admit that also made me feel better :)
I also found watching kids movies helped. They are all funny and have a happy ending. Great for taking my mind off things. You'll figure out what works for you.
You're right about the wine or three. I didn't know it was a category one carcinogen until I was diagnosed!
Love and best wishes. Remember that most people diagnosed with breast cancer will survive it. <3