Calming nerves before sneaking out?

I know there's a lot of questions on here about how to sneak out, but one thing I need is advice on how to calm nerves beforehand. I've snuck out 5 times, I know how to do it, but tonight I am especially anxious. My anxiety had gotten so bad I'm shaking and my stomach hurts REALLY bad. I really wanna go out tonight, for specific reasons, and I'm sure I won't get caught if I can actually calm down. (And no I don't wanna hear why I shouldn't do it. I already know it's wrong. I just want an answer to my question. Thank you!)