Panic attacks...convincing myself I have a heart problem?

Well I started getting these annoying and very scary panic attacks back in late January early February. I got my very first panic attack January of 2010 after smoking weed, I don't smoke at all anymore. I never got another one after that, and this year I had chest pain and had a panic attack and ever since started getting them frequently on a daily basis. Not a day goes by that I don't think about panic attacks, when I wake up it's the first thing on my mind, and it stays on my mind till I go to sleep at night. Bed time is my favorite part of the day because I don't have to deal with the panic attacks. I've gotten at least 4 or 5 EKG's just this year and all of them have been normal. I always think there's something wrong with my heart, or it's beating too fast, or I worry about having cardiac arrythmia or hypertension or something crazy like that. These panic attacks have stole my life away from me. I had to quit a good job because of them. I don't want to take meds cause that's more dangerous than the panic attacks, and I am seeing a therapist but I think because I see her every 2 weeks, it's not really working. But I am so tired of living my life in this fear. Work is pointless to me cause I think what's the use in working and getting money when all that doesn't even matter when almost every minute of my life I'm on edge and anxious about my next panic attack. I guess I'm just afraid of what a panic attack can do to me, although doctors have said they can't do anything. Should I be this worried about this?