I am worried about the weight gain while on epilim. i have gained a lot off weight.

It prevents satiety: The issue with sodium valproate - in all it's forms, is that it often modifies the feeling of satiety - you never feel full. You need to eat a lot of high fiber foods which will help you feel more sated with fewer calories. Make sure to drink a plenty of water. Carefully measure your portion sizes (4oz meat, 1/2 cup cooked rice). This will keep your portions controlled. After meals - go walk!