Glad to hear you are ok. Must have been scary. I still can recall every fall I have taken clearly in my mind as if it just happen yesterday.

Keeping balance with one hand come with practice. Kind of like taking both hands off the bar bwhile moving forward. One thing you can try is to stop pedaling when you take one hand off your grip. Let the momentum of the bike keep the balance. Also keep you arm closer and lower to your side until you get better. Try to relax the grip of the hand that is still holding the handle bar.