But every sector has been ravaged by the stock market changes.

You just don’t know what you’re talking about. The S&P 500 is up like 25% over the same period. You’re just buying into specific sectors. Don’t do that. Buy market index funds or target date funds and stop trying to actively manage your retirement account. Also, you haven’t lost anything in value because you haven’t realized the losses by cashing out. It’s better for you currently if things are a lower price because you’re buying them at a discount.