I'm a bit worried about going overseas to Malaysia by plane....?

I'm 16. Firstly, I have a bit of a past of anxiety and obsessive compulsive disorder and a lot of panic attacks... and in a month I'm going to Malaysia with my school. It all seemed fine about 5 months ago when I asked my parents and they said yes but now that we've bought everything and alls been done I'm starting to get very nervous. I have never been on a plane before or out of the state and it's really starting to shake me up. I am starting to get cold feet and it's like one of those things that I just can't pull out of. :/ Please help me. What should I do? Any medication maybe to help me out? I'm just so afraid I'm going to freak out on the plane... 8 hour flight..