I've been taking 330 mg of ferrous fumarate every 12 hours, and i have been experiencing insomnia, can the medication be the cause? should i take it in the morning only to avoid insomnia?

Iron supplementation does not typically cause insomnia. But, to see if it is contributing, skip the night time dose one night and see if the insomnia persists. If you don’t have the insomnia on a night you don’t take the iron dose, then call the doctor who prescribed the iron and see what an alternative to this treatment would be. That doctor can also decide if 1 dose a day would be effective.