I Have Constant Discomfort In My Upper Centre Abdomen, It's

I have constant discomfort in my upper centre abdomen, it's been going on for almost three months. Constant nausea, I've lost 9 lbs without trying, I often have chills and sweats. This past weekend, for about 36 hours, I felt very ill, exhausted, pain in by entire abdomen and had a fever. This morning I am feeling better (back to just the constant abdominal discomfort and nausea). I am an otherwise healthy 56 female, exercise regularly, non smoker, social drinker 3-5 drinks/week.