If you have been having panic attacks for 4 years, you do need to see a doctor and see if there is anything else going on. Having panic attacks for so long and not seeking treatment can have severe affects on your body that are irreversible and serious. If you still don't want to see a doctor knowing that, then here a some things that might help you out.

1) Reduce the amount of caffeine in your diet. That includes pop, chocolate, and some over the counter pain killers (like Excedrin). Also, energy drinks (Monster, 5-Hour, etc.) and things that are like pure sugar. Caffeine increases heart rate and how fast your mind (seems) to be working. Increases in the heart rate like this can trigger panic attacks.

2) Breathing exercises. When you feel a panic attack coming on or after one has already started, focus on your breathing. Inhale. Exhale. Inhale. Exhale. Try practicing breathe control while you're feeling well. You will get light-headed most likely, but when you're having a panic attack you won't so don't worry about that.

3) Exercise. Light daily exercise has shown to help people with panic disorder minimize the severity and frequency of their attacks.