I know I would be tracking down the identity of this deputy, and exploring my legal options against him. What he did appears to be so wrong on so many levels, but then we don't know the whole story.
I think if this had happened to me, in the setting described, I would also contact a lawyer. But I would ask the lawyer to send the Deputy a letter stating it was legal for me to carry, what recourse I could have against the deputy and the department and then ask for an appoligy from the deputy and the sherrif. I really do not think I would try to sue.
I remember a case I was involved with. We were doing searches at the gate of a military installation. I asked a guy "Whats in the bag?" and he showed me what was in the bag. He had a whole lot of things in his bag he should not have had. His lawyer tried to claim illegal search, but the military lawyer said that would not fly, because I asked him "Whats in the Bag?" instead of "Show me whats in the Bag."
Sometimes, how you ask a question is just as important as what you ask.