Sorry to read this.

1. Not clear that a bike touring forum is the best place to address what might be a case of dysfunctional anxiety. You may want to read about anxiety in general and figure a way to cope as best possible
2. Interesting question wrt safety. I've tried to find hard data to assess the risk but could't find much. As you can probably guess, most cycling occurs in cities, which is where most injuries are reported. But there are no reported "hazard rate" for bicycle tourers (such as, 1 fatality per 1 000 000 cycled miles).
3. One way to assess the relative risk is provided by the statement (from the CDC I believe) that cycling is recommended because it increases life expectancy due to the benefits of exercising. Implicit is that the risk of cycling injury is rather low.
4. You refer to being hit by a car. IIRC, less than 25% of cycling injuries involve a car. Falls due to poor handling, poor road conditions, or intoxication are the leading causes of injury. You are in control of these (well, you can ride more carefully on bad roads). So, anxiety will make you safer. Silver lining.