This has happened to me, but the items reappeared in intentory within 24 hours. Once I tried to rez a doll, not realizing that I could only wear or add it, and poof! It reappeared in inventory upon login the next day, making me happy again. And I put things in the wrong folders all the time. Do a search of your inventory. If this happened on land you own or rent, try going to world, area search, find, and then searching under your name as owner of the item. I've had things disappear into my platform and found them that way. Also a good thing to know if you're having prim probs on your land, there could be lost items using up a lot of prims. Stuff like jewelry is mad primmy. Hope this helps you.