Susie,
Tray and I are both in that same boat - both of us have lost money. I'm down about 1/3, similar to you. Tray is down about 1/4 (she invests a little more conservative than I do).
But we're not panicking yet. We both have many years before retirement yet, and it will come back. I don't know if you follow any financial advisers (some of the popular ones out there do free newsletters and such). Anyhow we receive email newsletters from one that I particularly enjoy called "Everyday Cheapskate". You might check into it.
But she is of the same mindset - don't panic. It will come back. And look at the bright side. For now we are buying low. :)
Emms