<s>[INST] I have extreme thirst and extreme fatigue.  Headaches and neck/back aches.  Just recently fever is associated as well.  Mind cloudiness....like I cant keep things straight.  Blood work showed very low iron levels, but all else comes back ok.  Blood pressure ok, sugar ok, oxygen levels ok....  Im 38 F and have always been genually healthy. [/INST] Hi and welcome to Chat Doctor.You should do more detailed blood work and check your urine and hormonal levels. It can also be any kind of respiratory or urinary infection. Sometimes even the exact infection site can't be found. It sounds to me now like viral infection which can cause headache and neck pain, bones pain, fever etc. You should Chat Doctor.  If symptoms persist you should visit infectiologist for further testing. Wish you good health. </s>