I get those a lot. I've been in the hospital before because it got so bad. Sometimes it just seems that nothing at all triggers it and I can feel my heart racing, can't breathe, and just feel like I am dying. It's horrible.

Diet can make a difference. Cut down on sugars/carbs, try to make sure your diet is balanced and cut down on artificial colours and flavors. Caffeine also can trigger panic attacks even if you have just a little. It varies by person but that's what I found helps me.

I really do not like to take pills but a low dose of xanax helped a lot. I take it before bed since it puts me to sleep.

Also, lowering stress can help.

I second the lavender. It's awesome for pretty much anything. I drink a lot of lavender tea and use a lot of lavender oil.