@padmasana I believe you can consider it addiction if it has a negative impact in your life. Most researches related to porn are circunstancial, so they don't really provide any real evidence to support if porn is good or bad, so as it stands it ins't a physical or mental health issue.
So, it's all up to the individual to decide. If you don't do stuff you need to do because you need to watch porn, if watching porn hurts your relationships, or anything like that, I'd say it's time for you to find something else. But if porn is just something you like to do in your free time, and you just think you do it a lot, it's not a big deal.
Again, in short, if watching porn affects your life negatively, then it's a serious problem that you should take care of, if it's just an activity you do on your spare time because you enjoy it, there's no real need to stop doing it.
Now how to deal with it, depends on how porn affects you. If it's an actual addiction, then I'd say try getting some professional help. If it's something you do on your free time but you want to do less, finding other hobbies and filling up your time with other things usually helps.