Remember that it's all in your head. Try to figure out what's reality and what's not even though that's hard. Try to get your mind off of the situation of what's going on, for example try playing video games, or reading a book, maybe talking to family members and if that's not working maybe take a nap and see how you feel when you wake up

For me I grab something rough and rub it until I feel it like the edge of a table or an ugly curtain, other times when I start to panic and I get a pretty good size of salt and toss it on my tongue the shock from how salty it is always grounds me you can even do it with something sour.