Steve A, just a thought but I'd imagine when you started paying into your plan you felt your choice of investment suited your attitude to risk. These are very testing times and the fact that you are so worried about it now implies you may have been more risk averse than you first thought.
You'll need to address how you are going to direct future payments so come hell or high water you are comfortable with it and hopefully you will have a number of years left to retirement in which to recoup your losses.
Meet with your financial adviser (or find a new one)for a recommendation. Pension provision is not a bad idea - yes even in these volatile markets but equally rewarding is the satisfaction and peace of mind gained from being debt free.
Best of luck with your decision.