Hi Fiona,
It's hard to take in isn't it. So many thoughts all at once..I also had ductal (and lobular) invasive with surgery ( lumpectomy) and am in radiation treatment now. 3 months on since diagnosis and this is what I can suggest:
1. Allow yourself to have a weep when you need to...
2. When feeling overwhelmed, try to just focus on breath for even a few minutes when your mind starts running amok. It will help calm you.
3. Do yoga nidra... It's a guided relaxation and teaches you how to watch your breath and body. Find a great yoga teacher who you like or buy a recommended CD ( "big shakti"has a great yoga nidra CD and website..)
4. App by Andrew Johnson called : Visualize healing. It's self hypnosis/ relaxation. He has others. This app was recommended to me by another friend with breast ca and I have shared with others who also highly rate it.
Heartfelt thoughts