I think there are two ways to know if you're addicted to anything.
1. Is wanting it keeping you from functioning in your daily life or interferring with you being responsible and accountable to others.
2. You become over the top anxious or ill when you can't have it.
Your personality shifts to a place where people who know you can't figure out why you're acting nuts.
Some would say it's possible to be a "functioning addict".
The type of person who manages to keep it all together while going over the top with their personal habit, alcohol, drugs, or sex.