The whole point of using a passive strategy (i.e. index fund) is NOT to worry. If you are in the stock market, then the possibility of a bad year or two is not a surprise or cause for alarm.

If I wanted to worry, I would actively manage my portfolio. If I wanted to eliminate risk, I would sock it in my underwear drawer.

You may want to reevaluate your risk profile, and see if your investments are appropriate for the level of risk you are willing to bear.

Hang in there! In 30 years, you will thank yourself.

Brian