Hi killburn,
that sounds like the bug we are discussing here:
Items Disappearing from Stash and Inventory
There is no way to recover your loses. But if you don’t take care, you will lose more and more items over time by this bug. Looks like it is linked to an upper limit of the savefile of your character. You should not store as many 1x1 items in your stash and inventory as you are probably doing right now.
All the best for your journey.