Scared...

I went to the doctor yesterday because I had been in an accident a week before and wanted to make sure my neck and back were okay. I had found a knot on the left side of my neck and I wanted that checked. While feeling my neck, my doctor found a lump I hadn't and said it was a lymph node. She then found the one I had already noticed and said it was a lymph node as well. Having no idea what that meant or could mean, I said nothing. She checked me for infection or signs of virus, but found none. She said she would put me on antibiotics for a week and then reevaluate in 10 days. I began reading on lymph nodes at home and realized that I have some symptoms that make this more worrisome. I have dealt with fatigue for a year now. The type that keeps me in bed for over 12 hours a day. The nodes that are swollen are firm and not tender to touch. One is located just above my clavicle and the other at the base of my neck, both on the left side. Should I push for a test of some sort, or wait to see if the antibiotics work? I am feeling stressed, but trying to keep my paranoia in check. Thanks:)