abnormal mamogram(mammogram)

I will try to make this short as possible. I have a family history of breast cancer (mother, aunt, cousin) and due to this had my first mamogram (mammogram) in 2003 at the age of 32. I am now 38 and recently went back in for a routine screening and have been called back in for additional imaging and a ultrasound. The nurse explained that a nodule was present that was not there in my last mamogram (mammogram). What will they be looking for with the additional screening? I am trying to not be overly concerned but it is very tough.

[iam1butterfly]

The additional screening... which may include a diagnostic mammogram, renders magnified views as well as views from different angles of the area in question.
With these additional views, the doctors can have a better idea of what they're looking at. Based on that, the doctor(s) would determine what course of action is deemed to be the best.
Having a biopsy (needle/ aspiration or surgical/ excision) may be the recommendation and would conclusively determine the nature of the growth.
Or, it might be suggested that you wait (usually, 6 months) then, return for a  follow-up diagnostic exam (i.e. mammogram, ultrasound or MRI) to see if there has been any changes. If no changes are noted; then, they usually keep monitoring the growth with follow-up exams. If there's been a change; then, a biopsy would be the next likely step.
Take care.