So your company has had a layoff recently, and you fear another, or you are simply afraid that they will in the future. What should you do? Any suggestions?
First, it is good that you are concerned. A layoff, when experienced personally, can be very traumatic and disruptive. Being afraid of one can also be very disruptive, especially if it causes you to become unproductive. A situation that can spiral into becoming a target for the layoff, especially if your performance suffers. Remember the phrase from Dune, "Fear is the mind-killer"? In some sense, that may apply to you.
To start, try to spend some time quietly and analytically analyzing the situation. For a moment, try to get your emotions out of the situation and look at yourself and the situation from outside of yourself. You can try to analyze the health of the company. Are they failing? Is the ship sinking? Is it worth waiting around, or should you start looking?
Also, look at your performance. Are you brand new with no track record, or have you been performing well? Logic would usually point towards keeping high performers and letting others go. What is your role? Are you valued for a special skill, or do you work on a key piece of technology? Some aspects of your work should protect you.
Now, if you've logically deduced that you should be set, you can relax a bit. But not completely. There can be a lot of arbitrariness in layoffs, so keep that in mind. Remember, you are looking to reduce your anxiety and fear. You can't ultimately control what happens, but you can control how you are handling that situation and how you are thinking about the potential future.
Hopefully, at this point, you've reduced some of your anxiety by looking at things logically. Realizing that you still might not know what will happen, I suggest you take this opportunity to refocus on your work. Others may still be frozen in fear or panicking, but you don't need to. This can be a time to really shine. Focus on your work, what you've accomplished, and what is in front of you. You may need to start looking for another role, so why not keep the momentum going with the current one? Maybe there is work not being done that you can focus on to learn more. Maybe some people are falling back, and you can pick up the slack. You never know that this renewed burst of energy could shine a positive light on you, and you can survive the next round. You may still lose in a massive layoff, but you will have given it a good try and hopefully have more on your resume to show for it.
What I'm really suggesting here is that you focus on what you can control. In the end, if the company fails or you get laid off before that, you are probably not going to prevent either personally. You can control how you show up. Panicked and worried, or focused and productive. Choose later, and you'll have more to show for it.