@Caroline71 This time after diagnosis but before heading into treatment is really really hard. I spent that time veering from fog to absolute despair. Somehow, once you start treatment, the anxiety while not going away, does tend to calm a bit for most people. I'm guessing that you know who you have been referred to - give them a call and find out your appointment time - the staff should be used to people who are anxious.
It sounds to me that you have a lot of trauma to deal with having this come so soon after your father's sudden death. Do you have a psychologist/counsellor? If not, I would suggest that you try to get in to see someone who deals with cancer patients & families. You can get a mental health care plan from your GP to offset some of the costs. And I know at the moment that probably seems too much to even contemplate but talk to your GP or oncologist - they often know of someone who they can recommend.
The thought of leaving our kids is an awful one. It has been my shadow throughout and I don't know if it ever goes away. On the other hand, my kids have been amazing since my diagnosis 18 months ago. They still drive me to distraction at times and it certainly has affected them but they have really risen to the occasion when needed.
As the others have said - come here when you need information, want to vent or even have a laugh. We get it.