Please try to calm your fears. Like Donna said, 80% of lumps are benign. I recently had to go back for more testing and films because of heavy microcalicifications found in my normal breast. Microcalcifications are ususally caused from many things, but when they cluster together then you really need more testing. An ultra sound will give you and the docs some answers. If there is a lump, then biopsy is the only way to get the right answers. Insist on a biopsy.
I too will have you in my prayers and please keep us updated. We are here for you. If you haven't already and you want too, please post to the roll call thread at the top of the listing page and let us know about you.
Hope to see your post soon with good news.
Two are better than one, because they have a good return for their work: if one falls down, his friend can help him up. Ecclesiastes 4:9-10