regarding anxiety: I learned from my kid's treatment for OCD (which is an anxiety-triggered condition):
Giving in to anxiety only makes it stronger. Denying it, "speaking back to it," makes it weaker.
And, "exposure therapy" works for anxiety--the human psyche can be at a fever-pitch of anxiety only so long, and it wears out. That's good for the anxiety.
Drive. And tell your mother, "I do not want you to talk to me about this anymore. Its your hangup, and I really do not want you to make this mine."
I grew up with a mother who refused to worry; I married into a MIL who worries. I get angry when she says, "Call me when you get there, so I know you're safe." I believe in the "no news is good news" idea very strongly. I've flat-out refused to call, even if I'm driving home on a snowy night, saying, "If I do have trouble I can't handle, I -will- call; I won't be stupid and try to tough it out."
I've given in a few times, when weather was really bad, but I stuck to my guns often enough that she gave up, and now I don't think it even occurs to her to worry unless the weather is really, really lousy.
And this is really important, I believe:
t also helps to subtly show her how much a certain thing is done and how common it is, and how it usually is fine. The more something is seen as "the norm," the more it seems to settle my mom's fears, at least.
In many situations in which people act irrationally or unreasonably, I think the most effective thing to do is to insist upon acting in a rational or reasonable manner. Don't try to argue with their irrationality--that only sends the subtle message that she must be right after all, or at least that she has the power to determine what you do, since you seem to need to persuade her away from her stance.
I don't even think you should acknowledge her fear, not anymore. You're not her therapist.
Just say, "Mom, please don't dump your hangup on me," and leave the conversation. And drive.