portal to nether world continuously dropping me into a lava lake dispite overworld build site of such

I created a portal to the nether world. The first time it dropped me in the middle of a lava lake resulting in the loss of all of my hard earned supplies not only to mention the time acquiring them in the real world. I re-spawned to the over world removed one block & replaced it thinking it would change the arrival point of entry in the nether world it remained the same . I returned to the over world again , rebuilding the portal in a different location far away from the original building site, re entered the portal to discover it dropped me in the same exact location 3 times total... I gave up the quest to say the least . Thank you for any assistance you can provide.