In The Last 4 Months Have Lost 30 Pounds. Have

In the last 4 months have lost 30 pounds. Have very dry mouth all the time and do not produce much saliva. Drink lots of water to keep mouth from becoming dry. Have no appetite. Have nasty taste in my mouth all the time, sometimes metallic, mostly just nasty. Dentist says this is not uncommon for someone my age, but very concerned about unwanted weight loss and no appetite. Also went to hospital a month ago with pain in back and stomach was diagnosed with acid reflux. Thanks for your advice!