Hi thank you for posting your query.I have gone through your details and according to my opinion first you have to get your thyroid profile check before taking any thyroid medications and moreover weight gain or weight loss depends upon BMR rate so keep your metabolism strong by eating a well balanced diet and doing yoga. Here I am suggesting few effective remedies for gaining weight Have 1 tbsp chyavanprash daily. Have banana or banana with a glass of milk daily. Soak few almonds,raisins overnight and consume in the morning. If you are non vegetarian you can have eggs. Take 1 tbsp shatavari churn and 1 tbsp ashwagandha churn daily with milk. Take a light nap in noon after meals. Boost your energy by walking daily for 30 minutes. You can have ayurvedic preparations like shatavari kappa,ashwagandha churn ,kushmanda avaleha,yashtimadhu. Have a high calorie diet Consume mango,litchi,grapes,banana frequently in your diet. Take ghee,peanut butter ,cheese,paneer for gaining weight. Practise sarvangasan,bhujangasan,shavasan,yoga nidra daily. Hope this answer is useful to you. Regards Dr.Pallavi