So helpful to have understanding responses so quickly on here. Thanks for the flowers @iserbrown <3.
Yes, @Afraser, I felt really in control from the moment that the ultrasound lady started to explain what she was seeing and checking. I was so pleased that she explained rather than leaving me in limbo. I knew she was giving extra attention to an area and would gave gone home much more worried if she had not said anything. She gave me sensible info without being alarming and that was appreciated.
Driving home I was so clear in my thinking and have since spoken with my GP and been in touch with my breast surgeon. The knowledge that I have from my previous experience and from others on here too has helped enormously to give me a feeling of control over the new situation. Hopefully it is not cancer and I can just have a mastectomy and get on with life pretty quickly. Fingers crossed.