What Causes Nausea And Excessive Salivation?

I am 79. Always been healthy with a lot of energy , 2 months ago I developed waves off nausea with extensive salivating. No vomiting. Loss of weight, chills, and basically no appetite. I have fallen three times during thsi time span.. I lost two wisdom teeth(just broke off, crowns include. They are now infested and due for extraction next week. I have been taking anti biotic. Also my memory has been a little off. Went to my OMG doctor had a blood test(they checked my liver, lungs, pancreus etc. all normal. X-ray of chest no problems, administered an ultrsound which was normal. Now they are talking barium upper gi. I m sick and tired of no results. This isn t in my mind only. I also have a cold and cough. I am taking mess for upset tummy, and cough. I may feel allittle better but not much. Any suggestions? Thank you. Bob Jones