Feel the body, really ground in there, especially the lower body. Feel butt, legs, feet, toes. Give the toes a wiggle.
Then take some slow, deep breaths, ideally with your eyes closed. Focus on the rhythm & sensations of the breath. Try to power the breaths from the belly, inhale through the nose, exhale through the mouth. Feel free to sigh & moan as you exhale, to express & release some of the pain & stress.
Thoughts will come up about what to do, what's going to happen, etc. Let them go. Return to your body focus: feel into the lower body, focus on slow & deep breathing. When it does come time to make decisions, you'll make much better decisions if you've grounded & centered first.
Other things to try:
cold shower & ice bucket dips
rapid deep breathing (see Wim Hof method)
pleasant distractions, e.g. fave lighthearted shows & music & movies
Do whatever helps you ride out the storm in the spirits of mercy & self-love. This too shall pass. In the meantime, do damage control & bring yourself whatever solace & stability you can.