RE: Never been so scared in my life!
Attacks on humans are very rare, they'd rather turn tail and exit. I understand the worry but bears are way more afraid of humans than we should be of them. That doesn't mean we shouldn't respect them, especially sows with cubs. I feel you did the right thing by making yourself appear larger and warning her. Yes, she could have charged but again, rare.
Look back and enjoy it as a great encounter. I've had run ins with many, many bears, they turn inside out to leave when talked to.