I have been sick my headache been for a week i now have a cough low grade fever and my right leg staying cold if i warm it my headache leaves why?

See a doctor: having an isolated cold limb does not sound like a good thing and you should see a doctor as soon as possible because having a clot in the leg can be a cause of a low grade fever. If the clot is breaking and sending small clots to the lungs, it might explain the cough. See a doctor ASAP especially if you have leg discoloration or pain.