First of all I want to say good job on keeping your head even though you may have wanted to freak out. That is the first thing to learn! Lol
I would ask for a few lunge-line lessons. These will help you figure out where your body needs to be and will do a lot for helping your balance. A lot of lunge line lessons are no stirrup lessons, but I would start off with your stirrups and once you are comfortable there, progress to no stirrup work. The nice thing about lunge-line lessons is that you can concentrate on yourself and not about controlling the horse. Good luck, and don't give up! You will get it!