No sex,no smiley face what gives?

Hello,I am concerned about my wife we are married 2 years now and with the last two months she has changed a lot ,she seems to be going to the bathroom 5 times during the nights,she is also cranky,And sleeps a lot also even when she sits down it the evening she is asleep for eight o'clock .She is only 29 im 39.im worried about her we haven't had sex in about 3 weeks now as she usually is asleep by the evening and when i told her to see a doctor she says noting is wrong and she is determined and wont go for me what is wrong with her is she bored of me is it me?