<human>: Could you distill the essence of the text into 1-3 sentences?

I apologize for any ranty language in this post, my heart only started beating again a few minutes ago. I was on my nightly jog with my chihuahua mix, Connie, when this giant dog comes barreling towards us on the sidewalk. I'm not exaggerating, either. This dog looked over 4 and a half feet tall and I'm only 5'3! My dog is a rescue, and, despite what the shelter said, she's still adjusting to being around other dogs--so I was doubly terrified. 

I didn't know what to do. I just froze, with Connie hiked up near my ears, heart in my throat. The dog's owner was *halfway down the block, nonchalantly striding towards us* without a care in the world. The only things going through my brain were 'how do I protect her?!' and 'oh my god I'm not tall enough to keep her out of his reach!'. In my head were all these scenarios where the dog goes for my Connie and blood would be just everywhere, my heart was going 100 miles a minute.

Thankfully, the dog was just a giant sweetheart, but for the 5 seconds it took me to realize that, I just sort of spun around in place awkwardly, trying to judge his intentions, keep him in front of me and away from Connie at the same time. After what seemed like a lifetime of this strange dance, his owner finally, finally arrived and leashed him, muttering, "You were fine, he wasn't going to hurt you." I think I may have yelled at him a bit when I found my voice, but it's all really a blur from there. 

In the case that a scenario like this repeats, what would be the right course of action? I also want to note that we weren't in a dog park, we were jogging on the sidewalk near my apartment complex.
<bot>: If an unfamiliar dog runs at you (and/or your dog) what is the best course of action? Should you stay still? Should you run? Should you bark/act aggressive?