Hi, I Woke Up Thismorning, Felt Fine, Went For A

Hi, I woke up thismorning, felt fine, went for a shower etc, got dressed, done my makeup but when I looked in the mirror I actually gave myself a fright thinking it was someone else. I looked so pale I didn't believe it was me for a second. I feel absolutely fine but have had family and friend say I look like I have seen a ghost. Why is this?
Thanks