Flying from LAX TO CPH

I am gonna be flying from LA to Copenhagen today for the first time in like 5 years and i’m very nervous because of the +10 hour flight over the water and across the world. How do i stop my self from having irrational thoughts while i’m up there so I don’t spiral and then have to sit in the plane for 10 hours with panic attacks and not being able to sleep? I just flew a week ago from Seatac to Burbank which went fine but this flight just feels like a whole new obstacle. If anyone wants to track me in 4 hours my flight is SK 932. Would be greatly appreciated :)