I used to travel alot for work in my and enjoyed it. About 6 years ago I had a panic attack driving on a major highway and have struggled with it not only as a driver but also as a passenger ever since. The last few years I have avoided all highway travel and am anxious as a passenger. 

I feel as though this instance opened an array of anxieties for me and I now struggle socially, and over think alot of situations. I used to fly for work and pleasure but in the past 3 years I have been unable to do so because of my fears.

In my current work I am still required to travel. Most of the work is close to my hometown, but some work requires 3 to 4 hour drives to other locations. I can manage these travels. My boss is aware of some of my issues. In the past I have forced them to remove me from a certain job that involved extended travel. I don't like to have to do this. it makes me feel weak and I feel like I am letting people down by making them change schedules. 

This past week I was told that I have to go do a job that is 15 hours away. The duration is a week. I was upset by the fact that in the past they wouldn't plan for me to be on jobs like these. What should I do? My gut is telling me to not go.