Goddess: at the risk of sounding negative - you probably will fall.....it probably will happen, and has happened to pretty much all of us. So don't be afraid of falling, just accept it. The best thing you can do is unclip Before you need to - it's always easier to clip back in and keep pedalling than to try and do that last-minute-panic-unclip thing. I unclip as I approach any intersection, crossing, anything that I'm unsure of etc etc. You can always rest your heel on the pedal until you decide if you need to stop or clip back in. Another thing you might try is to find a park or even put lots of blankets/pillows in your backyard, something soft - and then just fall.
I know you'll do just fine and pretty soon clipping/unclipping will happen without you even thinking about it! Heck - you'll wonder how you ever rode without clips and pretty soon you'll be reassuring someone else just how awesome they are!!
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"