How can I tell if I have fibromyalgia or MS? I have all the symptoms of fibro but most of the ones for MS as?

as well except that most of my joints crackle and make noise when I move. I am in constant pain and seem to be getting worse. I am extremely fatigued all day but have trouble sleeping at night and have bad repeating dreams that I can never remember. I am so tired of this that I am ready to anything to feel better and have even contemplated suicide just to make the pain go away. please help?