Portals are putting you at the same coordinates as the over world in the nether and end

I went through a nether portal I built in the end dungeon(for a nether highway). I arrived in the nether at the same coordinates as the over world but there wasn’t a nether portal and I fell into the lava. I ended up “fixing” the portals and didn’t have any more trouble with them for a while. After defeating the ender dragon and going back and forth from the end I came though the nether portal into the end dungeon and went through the portal. I was put at the same coordinates in the end as the portal in the over world without the obsidian platform. I fell into the end and lost all my gear.