Are you scared? If there is, put him in his favorite place, preferably a small, dark and closed place, or make him a cardboard box to drill into, which will make him feel more at ease. If he is close to someone, then someone will gently comfort him, talk to him, scratch him and relax.

If it's because of symptoms, it's best to take it to the hospital for examination, but I think it's mostly because of shock. Cats are very timid animals.