I wanted to go to the nether for the second time to search for some glowstone and I got teleported to what I first thought was a random place, but then turned out to be the exact cords as in the overworld. I had to go 3000 blocks in one direction and 500 in the other to find the nether portal again and get home. 

When I was teleported, there was no netherportal to be seen.