Nether portal

So there i was minding my own business on my realm, trying to link nether portals. Then i walk through the portal (with nice new enchanted gear) heard a bunch of damage noises but couldn't do a thing cause the terrain was still loading and i just died (with a totem of undying btw no revival). I go back to try to get my nice new gear and it's a new portal that's coordinates are the same as my overworld coordinates. I managed to come back to my original portal by stepping by through and for whatever reason with the 10 second time spand that this all happened all of my gear is gone. So it's either rapidly despond for whatever reason or teleported me somewhere intirely differen