I too found my lump quite by accident. It was 5 weeks after a clear mammogram. Mine was 1.9mm, grade 3, Es+ Her2+ invasive breast cancer. Radiotherapy is standard after lumpectomy for all types of cancers. Chemo is usually offered for a grade 3 cancer. Even though from the beginning I knew I would be having chemo. When finally told for sure I cried. Up until that point I think it's almost unreal...but the whole chemo things brings the "cancer reality" to the table.
I hope you go well with treatment. Any questions don't hesitate to ask. Kath x