Does it sound natural in English. Many thanks for your help
Last Friday I had my blood test to check how my thyirod gland is functioning. Before giving birth I was taking medication for my thyirod but after giving birth I stopped taking any medicine as I am afraid it can affect my milk.
My son is quite calm but get agitated when I change his nappy.

Question

Does it sound natural in English. Many thanks for your help
Last Friday I had my blood test to check how my thyirod gland is functioning. Before giving birth I was taking medication for my thyirod but after giving birth I stopped taking any medicine as I am afraid it can affect my milk.
My son is quite calm but get agitated when  I change his nappy.

Answer

Last Friday I had a blood test to check whether my thyirod gland was functioning properly. Before giving birth, I was taking medication for my thyirod, but after giving birth, I stopped taking any medicine as I was afraid that it could be bad for my milk.
My son was quite calm but got agitated when I changed his nappy.

Answer

Milka, you may wish to know that in American English a nappy is a diaper.