when i threw it in the lava, i felt unimaginable pain

All those diamonds you lost is painful...

me when im in the nether with all of my important diamond things with me and i die in a lava pool (this happened to me a few days ago)

my diamond sword had a really rare thing from the enchantment table it had no bookshelves and it gave fire aspect 1 smite 1 and unbreaking 2 smaller than a 0.2% chance

/give @s diamond
That’s what I would do