See your doctor about this. You might be able to switch to a different pill, or your doctor will be able to advise you about the best way to curb your appetite.
Drinking lots of water always helps, and try eating foods that are going to fill you up for longer, such as cereal and bananas. Try eating smaller meals, 4-6 times a day. Basically eat when you are hungry, but don't eat very much, eat it slowly, and keep asking yourself whether you are full yet. The brain takes 20 minutes to register the fact that you have eaten, so if you don't stop eating until you feel full, you have overeaten.