Have you ever got tested for Hypothyroidism ? Hypothyroidism causes excessive increase in weight gain in a short period. Sometimes stress also causes weight gain. Nausea is probably due to irritation in your alimentary canal after operation. Exposure to foreign bodies during operation can make body tissue over sensitive. The food digestion needs acids. By nauseated feeling, your body is trying to prevent eating till the intestine is healed, so that healing intestine will not be exposed to digestive enzymes and acid. There is also a possibility that there are thick scary tissue formed in intestine after operation that causes irritation. Ayurvedic treatment aims at first removing the cause of problem. If your intestine is fully healed and ready for digestion, you will not feel nauseated, but hungry ! For nausea, you must try to accelerate healing. Avoid hot, spicey, heavy, oily food. Try to be on milk diet for few days. Give rest to your intestine. Medicine - use Agastya Haritaki - 5 gm morning and evening with warm milk and water. It is a safe herbal preparation. Do not worry about weight gain right now. As for Hernia, getting operated is not a long term option. Hernia happens because your internal abdominal walls are not strong enough to support the organs. So it is like trying to collect water in a ballon. One prick and it will burst. What if your abdominal walls grow to be strong and capable of holding the internal mass. That will be the permanent cure. Kindly consult an Ayurvedic physician for more guidance. Probably your problem can be treated without another operation. I would recommend general body cleansing and detoxification therapy for 21 days. 1tsp of Triphala with warm water before bed. Best wishes!