Hi lilypup,
the good thing is that you could have developed this fear of the car earlier in your life, but luckily you didn't. And the fact - I assume you live in a rather large city, so public transport is probably well developed - that you don't absolutely need the car is a good thing too.
But I get what you mean - it probably feels like some sort of impairment, especially after you've been driving without any problem for so many years. Taking driving lessons again doesn't sound like a bad idea at all. You'll feel safe knowing that you're not the only one having the pedals and usually people are gentler when they see the driving school sign on a car. If you feel up to it, perhaps try to follow the plan your therapist and you set up, for example by taking short drives in residential zones, peripheral roads - wherever and whenever you feel comfortable, but as you would eat for a diet (less but more often). I think asking someone for company could be of great help too. They could help you see things more objectively, e.g. when you're pulling out of a parking, remind you that the other cars have brakes too!