How can I overcome this extreme anxiety from my upcoming travels?

In 3 weeks, I’m flying across the country (to a hell hole that I desperately fled from years ago) to dig up old nightmares about an abusive stepfather in court. As if this isn’t bad enough, I’m also completely broke and might not have a flight buddy (I’m terrified of air travel), my final exams are that week and I haven’t even been able to talk to my instructors about it because an exact date isn’t lined up yet. Nobody seems to care that I’m in danger of completely screwing up my grades. Nobody wants to lend a hand to take me to the airport. And believe me, I’m not doing all this for pleasure. The cherry on top—I’m trying to quit smoking.
How do you deal with uncooperative relatives, an empty, bank account, flying, potential failing grades and a hand that constantly reaches for the cigarettes? If you have any experience in any of this, it would be greatly appreciated. Even words of encouragement. I’m so nervous that everything’s just going to hell in a handbasket.