Somthing In The Water?

Ok, I'll start of by saying this happened to me just less than an hour ago, it didn't take l ong to get home after this happend.

At around 4:00pm I decided to go to the pool, so I went and swam. I love to swim so I didn't care about time, but it started to get dark, and cold.. I was alone at the pool and I was doing laps. I didn't like the deep end at all, swimming towards it was like dying, swimming into this bright light, but above the water it was dark, darker than the other parts of the pool area. I was at the deep end, just stopping to breathe. Now I wish I didn't take that breath...I yawned because I was getting tired and in the middle of the yawn I felt like something was pulling on my foot, pulling me underwater. I was dragged underwater mid-yawn, I couldn't breath, and I couldn't see even though my eyes were wide open, when I was let go I surfaced. Above me I saw a black shadow, just standing over me. I had seen this shadow before, in my dreams, nightmares. I swam away faster than I ever dreamed I could and quickly ran home and to my computer hoping my brother would be on.