Same thing happened to me last night. I'm screwed as well, because it looks like you cant actually swim back to shore from that far away. But I did notice that after a while, my body temperature was so low that I started losing blood at about 3 points every two seconds. So eventually I will die, but at 7500 remaining blood, it's gonna take a while. Why the fuck did they have to get rid of the respawn button?? <_<