What Causes Rash All Over Legs And Arms?

I have several symptoms i had a rash all over legs and arms. Then woke up sore all over including fingers and feet. My lymph nodes are sore and swollen behind ears. My knees really hurt to bend during this as well. They are getting better but my fingers wrists and forearms are still stiff and sore. I am going to go to urgent care when they open but am very scared. What do you think?