I’m sorry you fell.
I would echo Steve’s thoughts and go to a park or area with a dedicated bike path where there is not much traffic (including other bikes) and practice there.
It is true. A sidewalk is way more tricky than the street since there are more obstacles and typically they are not well maintained. However in the streets the presence of cars can prove to be lethal.
Take your your wife and the kids to a bike trail next time. Assuming you don’t go on the weekends.
Also if you have a gym membership you can practice riding in their stationary bicycles. That will improve your strength and will make pedaling second nature. When you are in the stationary bike, you can also practice removing one feet of the bike and placing it back in. Again, to improve the gymnastics of moving inside the bike (I know, there is such a thing as moving in the bike). Practice standing up from the saddle (when in the stationary bike).
Practice, practice, practice.
By the time spring is around you will be fine.
Also do some push ups. Arm exercises. Just in case you fall so your upper body is strong. But practicing in the gym should do the trick.
Pablo