For the last few weeks to a month i have noticed a marked decreased in my appetite. I can only eat about half the amount of food i used to eat before i feel extremely full. Also, every morning i have nausea that wont go away until i eat, even though it makes food sound completely unappetizing. A Mild amount of bowel irritation has also come and gone a few times as well. The only medication i take is 20mg antidepressant tablets. (Citalopram Hydrobromide) Could this be something serious?