About four weeks ago I noticed a marble sized lump behind my ear. It was hard, didn't hurt, and wasn't red. Since then it has grown. I've developed night sweats, fatigue, and slight abdominable pain. My doctor seemed worried and set me up an appointment for next week. I'm worried its lymphoma, I have a huge history of cancer in my family, and I'm not sure if I'm freaking out for no reason. They tested me for mono, viral infections, and bacterial infections and everything was negative. What else could it be besides lymphoma?