28 yr old female hx of GERD...8 months ago had hpylori now symptoms again with nausea an loss of appetite. How likely would I be to have stomach cancer?

GERD is Chronic cond. Stomach cancer is unlikely to be the cause of your symptoms. it is not the first thing I would worry about. But you need to tell us if you are still taking your medication(Antacids) for GERD or have you stopped it? Most people need to continue taking antacids for the long haul as GERD is a chronic(life long) condition in most people. So try taking an antacid daily and hope the symptoms go away.