Hi,as you mentioned that since 3-4 year you are very thin .Did you loose any weight ,if yes then how much and frequency.
It is very important for us to understand.
In hperthyroidism , metabolism is very good. .It means if you eat normal diet but still unable to gain weight.
Next Steps
consult with me on practo .So that we can discuss on that
Health Tips
calculate calorie count /day what you eat and what is your requirement.
To make a balance between intake and requirement and out ( any physical activity)