I would really insist that your doctor helps with your weight. I find it very concerning that they are not concerned if you are overweight.
Someone told me that not eating much is as bad as eating bad foods. Your body, because it thinks it's being starved, tries to store as much of the food as it possibly can and therefore means you gain weight instead of losing. That is why most nutritionists suggest 5 small sized meals per day. It means that your body is receiving the nutrients it needs.
I would also suggest maybe looking at seeing a nutritionist or dietician (you should be able to get referral from your doctor and most are covered by insurance, or public assistance if you can prove disability). They can help you come up with a healthy eating and weight management plan, taking into account your allergies and health needs.