Newly diagnosed metastatic cancer

So, thought I would update here and also thank everyone for their kindness. I have now had my PET scan and it was discovered that my entire spine, some ribs, shoulder blade and sternum all have mets. It has taken me a little while to process and move past the initial fear and everything that comes with all of this. My kids have been amazing, and while I know it is scary for them I make sure to let them know that I am not giving up and that even though it may seem small things are looking up with regards to treatments. My eldest is 16yrs old and so has his L's and is loving being my chauffeur driving me the hour each way to the cancer clinic. It helps him get his hours up and allows me to not have to drive for everything. 
Tonight I am having a bit of scanxiety as I have a brain MRI booked for tomorrow. The radiologist assures me that it is a routine test for getting a baseline image, but at the moment it is very daunting as each scan has just shown more extensive cancer and I am so scared they will come back and tell me that it is in my brain.
On the positive the blockers alone so far have shrunk my breast mass from grapefruit sized to maybe large egg. So I am taking that as a win and a sign that with treatments I will be around for a while yet. My youngest kiddo is 10yrs so I would ideally like to at least see him get to adulthood. I have also now had 2 'mega dose' sessions of radiation, one on the ribs and one on the lower spine and pelvis. Feeling really optimistic about those as the rib one was last week and the rib that seems to have broken due to the cancer is not as painful.
Sorry for the jumbled thoughts, still processing but wanted to update.