What Causes Abdominal Bloating Along With Severe Constipation And Back Pain?

My doctor is telling me I have ibs,my symptoms are all day worse at night and in the morning,no urge to go to toilet,constipated most of the time,I also get such a painful back were I can t even walk,no sciatica,my tummy in the morning feel so heavy like someone putting pressure on it,I m in severe pain sometimes,had this for five years,I ve lost weight,I was ten stone now I m eight no matter what I eat do I can t put it back on,I m 5 5 height,and age forty one.I m struggling that much with pain I ve contemplated suicide.