Lower abdominal pain 2 years after a total hysterectomy

I had a total hysterectomy just over two years ago. Recently I have been having lower abdominal pains at night that have been so bad they wake me up. Usually I get them when I have not opened my bowels for a couple of days but it is not like a feeling of having to go to the toilet, it is more a sensation of contracting and being in labour. It is so bad it has caused me to pass out on a couple of occasions. Occaisionally I have had them during e day but it is usually at night. The pain that I get is normally where period pain occurs not actually in my abdomen. I am taking Climaval 2mg each morning. I have had my ovaries and fallopian tubes removed and they found fibroids when they did the histology.