So while doing a run ( and it wasn't shabby either, probably a PB ) I made a nether portal and spawned straight underground. I tried digging up in all directions but was under a massive lava pool! I was really frustrated and ended up stopping the run. Next time if this would happen, what should I do? I had no diamonds for a pickaxe so I couldn't destroy it and make a new one.

Back to overworld and build another one that far from the old one or just reset the run, that looks easier.

don't cling to seeds so much, just reset and go next

^^

i actually made a method to tower up through lava lakes, but it needs a ton of wood (like a stack), i can send a vid if you rly want

thx, all of you. i guess it was just bad luck tho, ill try again

You can just Reset, Usually just play the seeds in which there is a fortress near or bastion near.