I know it's hard but try and think nice happy thought and focus on the positives. Where are you going and what for? Try and think of what you have to look forward to when you get to your destination and also think how lucky you are. Many people will never get the opportunity to go on an airplane and experience different places. I understand that the anxiety about the flight is probably consuming any positive thoughts you could have but you have meds that will chill you out, air stewards are used to nervous flyers and know how to look after you. Hopefully with the pills you can fall asleep and when you wake up you will be there! If not then take plenty of things to try and keep you chilled out- books, magazines, music etc, anything that will help take the focus of your panic. Try and remember that flying is the safest form of transport. It helps me sometimes to look at statistics and figures in relation to travel which shows that flying is totally fine!
Good luck and let us know how you get on x