Since a few weeks, i have low appetite & i get full quickly when i eat. i also feel bloated and my bowel movements aren't smooth and quick. what could be causing this? worried about cancer?

Your symptoms suggest a GI problem, rather than cancer. I would have evaluation by a trusted physician to determine the cause.

It is not feasible to provide a meaningful opinion without taking additional history, physical examination and may be some tests. It would be prudent to see your doctor and discuss if you may be depressed. Counter-intuitive as it may seem, exercise may help. Start with low intensity exercise such as walking and gradually increase the intensity as tolerated. Drink more water. Wish you good health!