Hi there,
Mood changes , depression and decreased sex drive are the reported side effects of Yaz.In your case I feel there are some other problems winch are leading to these symptoms of depression, mood swings and decreased sex drive. You should try to avoid anxiety and stress. Seek professional help of a psychologist. Also consult a gynecologist and discuss about possible options of an alternative birth control method. Do keep us posted on how you are doing. Only a complete evaluation can help in confirming the diagnosis. Take care and regards!