weight

I had lost all my baby weight and a few extra pounds. Suddenly I gained 14 pounds in a week. How is this even possible? I've been eating healthy and drinking tons of water. What the heck man! I feel discouraged.... I wanted to try and lose some weight after this baby and figured the "extra pounds" I lost was a head start.... was anyone ever experienced such a drastic weight gain randomly? I'm wondering if it is water retention....