Isabelle is 30 years old and has a 9 month history of amenorrhoea, hirsutism and reduced libido. She is stressed about the lack of periods given she and her husband planned on starting a family soon. She has put the reduced libido down to stress around conceiving and says her mood is good in general. She also mentions some milk like discharge coming from both breasts and denies any breast lumps, skin changes or nipple changes.
Based on her history, what is the most likely diagnosis?