Suggest Medicine For Hypothyroidism, Hair Loss And Weight Gain

I have noticed that my hair is very thin, I have almost lost all my eyebrows , and the really bothersome thing is that I have very few top eye lashes left and no bottom ones so when it is windy especially in the spring time dirt goes into my eyes and I have scratches that I can see when I look at white surfaces. I have has bloodwork done and my thyroid levels are always low over the last 10 years .However my doctor wants to wait on starting anything until my levels are much lower .....when should someone start a medication for hypothyroidism. I m exhausted all the time, have gain weight over these 10 years even though I m active and I feel like my emotions are really off all the time.