Also, when I got my road bike, I changed the pedal system from SPD-R's (a once popular version of SPD's for road bikes) to Speedplay because I found it MUCH easier to get in and out of pedals. Speedplays are not for everyone, but makes me wonder if you changed your SPD system to something else if it would be easier and give you more confidence on quick stops and hills ... just a thought.
You sound exactly like me.
Speedplays are so much easier to get in and out of. I love them.
Suzie, you might also try practicing quick stops. Imagine you have to stop quickly and practice getting out quickly.
Otherwise, it might be a good idea for you to stay out of situations that will put stress on you. Try to stay away from riding in groups, around dogs and kids, and cars. Try to ride in a controlled environment and get your confidence up on getting clipped out, before throwing in other "obstacles".
Good luck Suzie!
"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather, to skid in broadside thoroughly used-up, totally worn out, and loudly proclaiming: WOW WHAT A RIDE!!!!"