Pcod and thyroid diet. Is my favourite.

Hi doctor I'm 26yr female I have thyroid since 3yrs taking 25mcg and it's control I'm testing it every 3 months range is normal since 1.5 yrs , my periods are regular 27-30 days cycle , I am polycystic as well . I have done changes to my lifestyle since 1 yr which has led to my overall health development I'm underweight weighing about 44kg , so I'm often confused with diet as to what to eat and not to eat pcod and thyroid as I want gain weight healthy way . My lifestyle is as follow Daily walk 15 min , 10 min yoga Breakfast - usually South Indian but I add 1 banana or egg with it followed by tea or coffee Post breakfast after an hour I have fry fruits milkshake with peanut butter. Lunch - Basic home cooked with salad curd Evening - tea or coffee Dinner - Indian food usually roti Kindly let me know which are food I should avoid n should I avoid milk as milk is my favourite.