lymphadenopathy, unknown cause. should i go with p.e.t.?

Authenticity suspected lymphoma, f.n.a. suboptimal, excisional of same lymph node showed no malignancy, cat scratch disease, or granulomatous inflamation, but pathology says nonspecific reactive follicular and sinus histocytic hyperplasia with fibrosis and fatty infiltration. Surgeon says get p.e.t. scan, primary doc says I'm fine. Neck, groin, and chest areas all have nodes that are enlarged, some hard, i don't have insurance, is there other tests that can be done to rule out cancer before I do a p.e.t. ? Please help. I also have soaking night sweats and random fevers, and am losing weight......7 pounds in one week. Cbc and ct of chest ok.