Floating in the endless Blue

"I was swimming in a huge pool, but it didn't feel like a normal pool. I couldn't see the other side, and the water just kept going. I remember thinking I should probably get out, but I wasn't really scared. I just kept swimming. For some reason I was wearing my normal clothes. They weren't heavy at all, though. I could move through the water easily, almost like I was floating more than swimming. Then suddenly I was in the ocean, even though I don't remember leaving the pool. There was someone swimming ahead of me. I couldn't see their face, but I was trying to catch up. Every time I got close, they seemed farther away. Then I stopped trying and just floated on my back. The sky looked really strange, kind of gray and bright at the same time. I remember feeling completely calm. Then I heard someone calling me from somewhere behind me. I turned around, but there was nobody there. I woke up a few seconds later."