After entering the Nether is it possible to trap yourself without a way back to the overworld except via death or game commands?
I know it's possible to relight an extinguished Nether portal using flint/steel or even a Ghast's fireball but what can you do if your Nether portal is destroyed?
I was, rather foolishly, moving the only Nether portal I had from one point in my Nether base to another without spare obsidian. Using diamond tools I had dismantled the Nether portal and was in the process of moving it to a more secure room in my fort when I accidentally pressed the "drop" button on my keyboard. Because of my bad luck I had dropped the obsidian over a pool of lava - making it irretrievable - and no longer have enough to construct a new portal.
There was a series of mistakes that led to this happening: not having a backup portal, not bringing spare obsidian, previously demolishing the four corners of the portal such that those pieces of obsidian cannot be used. In spite of my errors, is there any way I can still escape the Nether or will I need to kill my character and have them respawn in the Overworld?
This question is intended for a survival singleplayer but answers can be encompass survival multiplayer too.