It's great that you are feeling better, and all without medication too. Everyone wants to be like this. Some try and are successful, but others can't do it on their own or with therapy alone.
Medication is prescribed by the doctor who may prescribe according to the individual's diagnosis and severity of the panic attacks. Panic attacks are often co-morbid (occurring with) other conditions, such as severe depression, bipolar disorder, etc.
Remember that panic attacks are only now "coming out of the closet" and into our everyday vocabulary. As you hear more and more about it, you will discover that you are not alone. Some people have gone untreated for years, as attested to by some of the posts on our board, and their condition may have worsened over time. However as it becomes demystified and recognized in society, and people find proper treatment when they need it, you will discover other people like yourself.