What Causes Itchy Blisters, Severe Fatigue And Heaviness In Legs?

Hello, I recently had what doctors thought was shingles. I had blistery looking hives on my torso area that were painful and itchy. The test results came back negative. All of the blisters have scabbed over. I have extreme exhaustion. I have never been so tired in my life. My arms and legs seem very heavy and somewhat difficult to move. My neck is stiff and I ran a low grade fever for 3 days.