I seem to get hungry half an hour after i just ate. my stomach growls and feels empty. might it be antidepressant ?

Depends: Hunger after eating might be a physiological predisposition (genetic) triggers by environmental factors. What you ate (eg lacking fiber or dense nutrients) is more likely the source than a medication. Without knowing which antidepressant you are on, one cannot answer if there is a relationship. There are some antidepressants that increase appetite ... you might actually just be still hungry.

Perhaps...: May be related to one of several things, or multiple factors. The fat/protein/carbohydrate ratio's of food directly affect how long it takes for you to feel satisfied after eating--fatty foods cause you to feel less "full" when compared to proteins or carbohydrates, whereas protein has the most effect of making you feel satisfied. Certain medications can increase appetite as well.