Magic

Maybe you're not looking at the Steam--->Community tab?

But did you craft them?

1) Steam Bug/Lag (more probable)
2) Someone hacked into your account. Check Inventory -> More -> Inventory History and then Gift History to see if someone didn't take them away

Your whole steam inventory disappeared, at least that's what i see. However don't worry, happened to me the first day of the sales, probably just a temporary bug. Wait and see if something changes in the next hours.

• Steam Community stability is laughable at best, especially under load, try to refresh the page in a minute or so.
• Cookies interfere with things a lot; check to see if your cache+cookies on any proper webbrowser are cleared.