One way to protect yourself and your portfolio in the face of a correction is to buy yourself time. Throughout human history, the market has always come back, given time. The question is how long will that recovery take. Given that the market rebounds, the only way to guarantee a loss in your portfolio is to sell low and buy high, which as we know is the opposite of what good investors do but what too many investors do in difficult markets.
How does one buy themselves time? I would argue preemptive financial planning is a solution. By having an adequate emergency account and liquidity, one can survive a turbulent market. By having parts of a portfolio that are comprised appropriately of high quality fixed income and cash equivalents based on your goals and objectives, one can avoid selling equities when things are going badly. Once the equity markets rebound, one then examines the portfolio and in a discipline manner, replenish the more conservative portions. That is hard to do once the market rebounds and equities are doing well, but is rewarding during times like these. Once the market corrects, logic dictates it's too late to make these changes. By being disciplined and having a plan, you can avoid the pain, if you're feeling it, next time.