You certainly don't need to feel that you shouldn't be worried .. we all worry at some point; it's a natural reaction. There is no reason that you can't have the mass removed if you wish ... Fibroadenomas are often removed if they become a problem. If this mass is indeed 8cm this would mean quite a loss of breast tissue and you would have to consider this also. Take care ....
You are not being ridiculous at all. Breast lumps are scary to all of us. I'm pro lumpectomy myself, as I've said, but if this mass is 8 cm rather than 8 mm, it is larger than I'm familiar with, but I'm no MD. It's really hard to wait for appointments for things like this, and then for the pathology report, isn't it? Almost torture. I'm sorry you're going through this anxiety. I will pray that the surgeon has confidence and reassuring words for you. Please report back after you see the surgeon and let us know what you find out.