Hi Kylie,
Many strange symptoms are reported with onset of PMS/PMDD, so I am not surprised that you experience anxiety while driving with someone else in control of the wheel.
The answer is quite simple: At its most basic roots, PMDD is actually a 'disease' or 'disorder' of our very complex nervous system! Hence anxiety, depression, emotional problems, hormonal problems, menstrual problems and all manner of physical symptoms which can thus manifest in most surprising ways.
Hope this helps to answer your question.
All the best,
Anthea