It sounds like a firearm averted an ass-whuppin'.
Four summers ago, I pulled into an empty gravel lot to a park just off a well traveled street on my way home from a friend's house at 0400 to use the bathroom (couldn't wait to get home). Parked my truck, left it running, and wandered 20' to the woodline. As I'm in the middle of my business, a large, older, lifted Blazer drives by, stops as they pass the lot, then reverse and pull in, driving straight toward my truck.
They stopped roughly 100 feet from my truck, and both doors opened and I saw them get out. If anyone says you can't stop midstream, they are wrong. I got back to my truck, reached in and took out the Glock I had placed on the floorboard, and stepped just outside my open door with it at low ready. Their lights were illuminating my truck, so I was certainly well lit with no mistake with what was in my hand. While I couldn't see them for descriptions, I could see their bodies as they passed the front of the truck and became backlit by their own headlights. One of them yelled, "Oh s***, he's got a gun!" and they both ran back, hopped into the Blazer, backed out quickly and then sped off down the road.
I'm sure I was in for a butt whoopin', but I wasn't going to stand around to find out. No, I didn't call 911, and I don't think I needed to. Looking back, would I have called? Probably not, but that's just me. Did I think I reacted properly? Yes, I do. I shared my incident just to let you know what I did when faced with something similar. Have I learned from it? Oh, yes, I have.
I think reacted accordingly. You were the one in the situation, and you felt what you felt; we can all give you advice on what to do or what we would've done, but ultimately no one can understand how you perceived the situation but you. If you can articulate your actions and justify what you did, then worry not.
Important thing to realize is that you recognized something wasn't right and at least you reacted to it. You didn't freeze up and you weren't in condition white. It sounds like if malice were to come your way that day, you were ready and willing to fight your way out of it. While deadly force may not have been appropriate at that level, the presence of your pistol may have dissuaded them from targeting you.