Sorry now I am switching to Microbiologist mode: you mentioned undulating fevers. Have they looked for the cause being a bacterium called Brucella it is the causative organism of brucellosis. It is a hard organism to treat, but it takes a person’s life away. Some people go insane because it gets so bad. It is difficult to treat BUT IT IS TREATABLE. The organism hides in macrophages away from your bodies immune system and replicates. When it burst out of the the cells it causes a fever. Then they move on to more cells and the fever disappears until the cells rupture. An infectious disease doctor can diagnose you by looking for antibodies to Brucella. Then you can start the appropriate treatment to get you life back.