malt stay away from google and BCC sites - otherwise you'll drive yourself nuts. However, once you get a plan and a proper diagnosis - then breast cancer care and macmillan are useful for deciding on treatment options - ie lumpectomy vs mx etc and different post op treatments.
My BC nurse said (when I found out my tumour was cancerous) said - and I quote directly "I bet you're already planning your funeral" .... turns out my 1.8cm lump (so marginally smaller than yours) is a common garden boring sort which they've all seen before. You go into hospital, get sorted, come out, they pump you with a few drugs, you feel a bit rough, then you're fine and you get on. I was unlucky to get cancer, but lucky to have a boring one.
IME if you're busy you tend not to dwell on stuff. I found out in the middle of my PGCE, which I'm back completing. I didnt have time to scratch my nose, let alone worry about cancer, I was too busy writing lesson plans etc. So..... find yourself something else to keep you focussed ... preferrably something that takes a bit of mental effort. I don't know what to suggest. I'm boring and like sudoku and jigsaws, but I realise that's not everyone's cup of tea.
But seriously, stay off the internet, except here.