Your "overreaction" was drawing your weapon unprovoked. Perhaps they were miscreants with bad intentions. But perhaps they were also just lost or looking for an address. They technically could have called in a complaint and the police would haven been out there after you, not them.
There was no overreaction here, and drawing said weapon was definitely provoked.
I know in Florida the law says you may not brandish your weapon unless you are threatened. The standard they will use if such an incident goes to court is what a reasonable person would have been thinking in that situation. The behavior of the other two men was definitely threatening enough to make a show of force, and to be ready to defend your life.
Now, I'm not a lawyer, I don't even play one on TV, I just have been around the block enough times to have some inkling of what would transpire in this instance if the police were called.
Now, as to calling the police, I would have done so. I know that others wouldn't, but that's their call when it comes time to make it.
The reasons I would have called the cops are:
1. It has been my experience over the years that the one who calls the police first is the one who will most likely be believed. Add to that that the "victim" in this case was were he was supposed to be and simply going about his normal daily life, and the two "assailants appeared to be out of place and looking for trouble, and your story gets more credible by the minute.
2. What if they were scared away but intend to lie in wait for you and catch you off guard next time. Having the police involved might just get some extra patrols in the area. It may not help, but it's like chicken soup, it couldn't hurt.
3. Once you have filled out a report you have already begun to build your self defense case. Obviously you aren't out looking for trouble, or trying to settle this yourself, because you did the right thing and called the authorities. You have taken steps to let the police handle it, and are just carrying the pistol as a self defense backup.
Those are my reasons, your mileage may vary.