Why did I loose all my muscle after getting badly sunburnt?

I had some nice pecs, chiseled abs, etc. But I spent a couple hrs at the pool on monday and got badly burnt all over my body. Only part that didnt burn was what my shorts covered. And now, three days later, it doesnt hurt as much. Im still burnt & what not, but my whole body has changed. My abs are barely visible and I got the flattest chest ever! Why?!?!?!?!