The doctor that diagnosed me believes that I have had fibro and many of its related illnesses the majority of my life. For years and years I have felt inexplicably crappy innumerable times. I simply accepted it. As it turns out, because of my illnesses, that is a rather apt description. Please, if this fits you, schedule an appointment with someone knowledgeable about these diseases to see if you have one or more of them.
Relief is possible.
Believe it or not, you don't have to feel as crappy all the time as you are used to feeling. Once, a couple years ago now probably, I read a novel in which one of the main characters redeveloped cancer, which the doctors thought had gone into remission. I remember utter puzzlement that most people apparently didn't consider their body their enemy. Over a month after quitting that job, I still have terrible hip pains, which I did not have before taking that job. I believe that the poor air quality of the city has also exacerbated my fibro and my allergies.