Prediction and Prophecy from a Pony

Twilight has a terrible nightmare and wonders whether or not it's a prediction

Twilight Sparkle has a terrible nightmare and wonders whether or not it's a prediction. It was only a week after "A Canterlot Wedding" and the scars had stayed. Is it a prophecy coming true? And if so, what will she do to prevent it?

Please read Tan575's "Irredeemably Rejected" prior to reading this. The story can be found in the link below