What Causes Chronic Weight Loss And Nausea?

HELLO! I am experiencing weight loss over the last month with daily nausea which seems to be much worse lately , and now I am experiencing frequent daily bowel movements as well. Overall I just feel unwell with muscle aches & pains. Although my appetite is not great I make sure to eat 3 meals & even try small snacks in between but still am losing. My weight has dropped from 116lbs to 109lbs. I am 5'2'', and 65 yrs. I would think a virus would have been over by now, Should I be concerned?