I just had the same issue. The game bugged out when I was just north of Balota earlier today. Quit playing and came back a few hours later. I spawned in the middle of the ocean and the respawn option isn't available.

Edit: I was able to swim to land, but it took around 30 minutes. I used 3rd person view underwater to see where the land under water looked to reach the surface and swam toward it.