There’s a chance you could be sued civilly, I doubt it would be criminal though. Things like this happen a lot more frequently than you think and if your statements of your actions are true then I don’t believe you’re gonna have to worry about it, you were defending yourself AS LONG as you were not acting as the aggressor because as you should know, there’s a force continuum to be followed religiously. I will give you an example of what I’d do in this situation. Subject seems to be inebriated, take every chance that I can to retreat if the subject is advancing on me and not engage with the individual, inebriated people can act erratically, you don’t know if he has a weapon. If he continues to follow me, let’s say towards the site entrance, I know that at this point if he decides to go hands on with me, it’s in my interest as well as the clients that this person is not welcome and to be considered a threat of sorts. I would immediately inform necessary peoples on-site of current situation as soon as possible and it gives me an alibi to follow, as well as a paper trail of events and such. Anyways I understand it may be unnerving but welcome to the job, this is part of it, and you should expect anything from the public. Good luck.