Hi Whitelily,
Well, you have a fear of flying - but you hardly need me to say that. With only a couple of days to go your options may be somewhat limited. There are clinical psychologists who treat this kind of problem all the time. It's possible you could find one in your area and make an emergency appointment? Other people find hypnosis a useful method.
Essentially, you are looking to anything that helps you to relax. As you already take medication I would caution against any more unless your doctor recommends it. Also, stay away from stimulant drinks like coffee or even cola drinks.
If you find music relaxing and you have a personal player - use this. Very often the waiting and the anticipation of flying is the hard part. On the day itself you are involved, focused on doing things, and you may (like many people find) actually enjoy yourself a lot more than you currently feel possible.
I'm sure you already know that flying is statistically one of the safest ways to travel. I know people trot this message out all the time, but there's no harm in restating it.
Maybe you'd like to post a message when you return?
Bon Voyage!