I have a fear of heights. I didn't realize how bad it was til we took a trip to Colorado....in an RV. Needless to say I was more than a little anxious at 12,000 feet as my husband was whipping around corners and then squealing to a stop along side the road just to take pictures. My IBS was out of control and I was furious with my husband. All I wanted to do was hide and be totally oblivious to anything else. I took Dramamine. Supposed to be for carsickness but it sure worked on everything for me. Took care of the anxiety, IBS, everything. I took two pills and slept the rest of the day til we got down to a more comfortable altitude. So...if someone else is driving and you don't mind sleeping through the rest of the day....Dramamine might be the answer. But get the "regular". There is also a non-drowsy kind. Just a thought. You also might want to try it BEFORE your long trip just to see how it affects you and for what length of time.