Hi, I Am 31 Years Old And Married For 5

Hi, I am 31 years old and married for 5 years.I am observing that my complexion is getting dark day by day and my hair is also falling too much. Usually my complexion is fair and used to have a good thick hair but now noticing my complexion is getting darker and my hair is also getting thin. I have thyroid for 2 years. Can you tell me the reason for this change and also the safety measures to be followed.
I follow a healthy diet routine,drinks lot of water and include fruits everyday in my diet.Is this change in my complexion is because of thyroid or any other hormonal imbalance ? Please clarify me.