Im scared of planes and have to face a 10 hour trip please help?

im petrified of planes i cryed through a two hour flight before, and i cant think of anything worse i cant even sit on a plane without my heart pounding and sweating. Im going from Gatwick, London to Barbados in the carribean. And its a trip of a lifetime but im scared silly just thinking about it what can i do? i love stealth at thorpe park so im not scared of heights...its just the chances of it dropping out of the sky and the bumpyness...*shudders* anyways thanks for reading all of this crap lol