Ghee is a good source of calories but should be consumed by the people who are physically active and do lots of cardio workout.
Since you have already gained weight and have thyroid disorder which aggregates the weight gain so ghee is not advisable in your case.
Foods to be avoided in thyroid disorder are
1) soyabean 2) raw cabbage 3) fatty foods 4) sugary foods 5) processed foods 6) coffee.
You should take the tablet empty stomach with water and should not take any thing for 1 hour.