I'm sorry to hear that.

Recently, the Inventory has been taking a while to fully load, so my first question is: Are you just waiting long enough for stuff to show up? If you're new, it shouldn't take very long, but sometimes I click through to some folder and for a little while, it looks like nothing's in there. Very disconcerting.
My second question is: Do you have the Debug menu open and, if so, have you been messing around in it? There is an option in there that I believe dumps everything in your Inventory, so..

I would think that would dump the Trash too, though, so.. I don't know. Obviously, I haven't experimented with that option.

If it's neither of those things and, after more people have given suggestions, the items still truly aren't anywhere in your Inventory, including the Trash, I would try contacting support..
Sometimes they roll back SL a little if there's an error and, because of that, you'll lose some recent work, but I don't think that's happened recently, and I don't think it would DELETE everything in your Inventory, anyway, so I don't think that's it..
There is no harm in bringing this to support after you try everything you can think of, though, because this sort of thing shouldn't happen ever, and by reporting it, you'll help ensure that it doesn't happen to anyone else.
