Is it all over your body? Or just where you may have been exposed to the sun? I had a very similar rash when I was pregnate with my youngest daughter. It was horribile, and got worse not better. It was an allergic reaction to the sun and or sun screen. Unfortunatley I had to go to a dermatologist and be put on steroids for the skin in order to see relief. Took two weeks..
If it's all over your body, look online at chicken pox signs and symptoms and other childhood diseases, also look at pictures. That will help you compare the rashes online to yours. If it's a childhood disease the good news is that it will be gone in a week or so., bad news is if it's a contagious one, you can't go back to work until it's cleared up. Hope this helps.