Sometimes I put my hand out and project all of the things that make me want to die to the other side, creating a barrier between us. Then I observe whatever remains and feel grounded.
Another one is focusing on keeping track of basic survival. Thinking about for how long you could survive with the amount of water and food you have in your system, which weapons you have, tools for shelter and fire, etc.
Another one is meditation, but that's usually getting dunked on 24/7 around these parts so I'm scared to bring it up. Anyway, the point in this case is to allow the anxiety and fear to be whilst noting them.
Another is making a mind-map of the worst case scenarios, write it down (important). Everything that you fear, what would happen to get there, etc.