Nether portal doesn't spawn in the nether

When I made a nether portal I went through but spawned above a lava lake on a tiny island in the soul sand valley so there were tons of ghasts and they ended up killing me.  So I decided to go back into the nether in creative and destroy the portal and all the land around it to hopefully get it to spawn on another landmass that's not surrounded by death, but when I went back through the portal it spawned me where the portal used to be but now there was no island for me to land on, and there was also no portal for me to get back, so I fell into the lava and died, the end.