No appetite at all? Hard to stomach meals... =(?

Im not sure how this all started but during the last year ive become increasingly worried about my eating habits. I never finish my meals, even the smallest ones. Ive tried to force it down but I get so sick, and I feel I might vomit. There was a time when I could have a meal from McDonald's, a double quarter pounder and a med. fry. Now I can only manage a small fry and half a burger! And Im full! I never really want to eat, except when I smell something awesome, I take a bite.... I go the whole day without thinking about food. How can I increase my appetite and not feel so bloated all the time?