need advice

Hi, I am a hospice nurse in need of advice from an oncology nurse. Two months ago I noticed my left breast was bigger than the right, tender and has a palpable lump. It swells and is more tender pre menstruation. I had an ultrasound and mamogram, both negative. My FP said nothing. I asked the office nurse to fax me the radiology reports. Impression states neg. for cysts or and solid mass, however there is prominent fibroglandular tissue in the area of palpable lump that needs close clinical follow up. When I called the nurse back to ask what this means, she stated "you just do that yourself, if you note any neww changes then notify the doctor". Does this sound right or am I just freaked because of my work area and knowledge? I am a healthy 43YO with no family hx of breast ca. I would appreciate any advice, thanks.