What Causes Headaches With Dizziness And Body Aches?

Hi, I am 22, and I woke up this morning with a slight headache. Initially I thought I was staring at the computer for too long so I took a walk. But whenever I stand up, the first few seconds, my head will feel light, but I do not faint. As the day progresses, I suddenly have body aches for no known reason. I have a temperature of 38 degrees, but my nose is not runny whatsoever. Is this flu?