Moose, having not been in the situation you describe I can't honestly say what I would have done. I don't own a firearm now. But, I did my share of shootin' when I was attending a higher education institution, so I understand and know ballistics and the damage a real gun of various calibers and types can do. The one thing that is a certainty is that whenever even one gun is in an area, the chances of a death resulting are increased. If the gun is made visible or handled during an altercation this chance increases further for numerous reasons and variables depending on the situation. Hence, the "last resort" philosophy of deadly weapons or, weapons with the potential to kill instantly. A knife can kill but not in the same way as a gun. A lead pipe can kill, a pencil can be used to kill, but not in the same way as a gun. You get my drift.
Not knowing where your police station was aside, could there have been another way? Why I ask is that as I mentally put myself into your situation I think in terms of, if I pull my gun, the chance of my child getting shot accidentally increases. Either by me, or by the other person who may also have a gun. And, who would most likely pull it if I pull mine. Kind of like nuclear weapons. So, for what was happening at that particular moment as you described, an escalation to sudden death was a bit risky. If say, the person following you was ramming your car and shouting death threats, well, that's another matter. Posturing or trying to intimidate you is another. But, you felt strongly enough to pull your gun after carrying for 18 years and not pulling all that time. So, that tells me that something was not sitting well with you in that situation. In short, I don't necessarily agree with the course of action you took, but I don't disagree either. It is variable to being there at the time. Obviously, something spooked you enough to do so. I don't know what I would do, but I think another solution would have presented itself for me.