Weight Gain worries

I've lived with Epilepsy for over 40 years now, was first diagnoised with Petit Mal as a child but now they are even less severe, I think they are now classified as absense siezures. I have had a weight problem for awhile now but have noticed over the past year it has gotten much worse. I take Tegretol & Depekene and know of the side-effect of weight gain with Tegretol. Just over a year ago I was diagnoised with Hemachromatosis (To much Iron in the blood). I was also diagnoised with a Cancer Tumor in my right kidney. Last year they removed my Right Kidney and its been since then that I've noticed the weight gain becoming worse and worse. Does anybody know if 1 Kidney and Epilepsy causes this to happen? I've read about Omega 3-6-9 helping to speed up your energy, I'm allergic to fish so the fish oil can't be taken, does anybody know if Flax Seed Oil with Omega 3-6-9 is just as good? I've also been reading about Xango being a good all natural energy booster. I've always been so afraid to take these for fear of interaction with medicine.