Pulled under the calm Lake

"I was swimming in a lake when something suddenly pulled me under. I don't know what it was. I tried to kick back up, but the water felt heavy and my arms barely moved. I could see the surface above me, getting farther away. I remember thinking, "This is it," and that scared me more than anything. I tried to scream, but only bubbles came out. Then, somehow, I stopped fighting. Everything became quiet. The water around me felt strangely warm, and I could hear my own heartbeat. The next thing I knew, I was lying on the shore coughing and trying to breathe. Someone was standing nearby, but when I looked up, the person suddenly disappeared. I sat up and looked at the lake. It was completely calm, like nothing had happened. I woke up taking a deep breath, almost surprised that I was still alive."