I Have Hypoglycemia With Severe Weight Loss. Im Always Being

i have hypoglycemia with severe weight loss. im always being told that i just need to change my diet but i have done so and the opposite has been happened. im losing weight and cant gain. i eat five meals a day and nothing. something else is wrong? is it a tumor or hereditary? my grandmother has high blood pressure, my dad has a thyroid problem (infrequent weight gain/loss) and my mother has fibroids/severe anemia.