Feeling shared

I went to my GP Friday to have my final examination after burning my breast and expected there to be no problems. As although I have small area that is redish left over from the scar and a very small lump, I just thought it was scar tissue but on examination my Doctor felt underneath the scar area that she could feel something more and said I think it is possibly scar tissue but dont want to take the chance. My head is saying it is cancer especially when she referred me for and urgent appointment to be seen within 2 weeks and by the time I got home they had contacted me with an appointment a week later. I would be greatful for any advice or reassurance as I am not getting much sleep at the moment.

Thanks