Hey man. I've been there, and let me tell you that it will get better. I'm 31 and am currently going through my second round of driving phobia. Like the other day I couldn't make it out of my neighborhood. And as you know, it's not the driving, it's the fear of having an attack that is crippling. The car, being isolating and potentially dangerous, makes it 100 times worse.
Here's what I suggest: 1) even though I am certain nothing is wrong with you physically, go see a doctor, just to confirm that. That alone will make you feel better. 2) this is easy to say, but try to reduce the stress in your life. I'm talking about taking care of things hanging over you, knock 'em out one by one. Life is struggle, and there's no avoiding anxiety, but see if you can't examine particular stressors that you hadn't addressed before. I'm talking buried stuff: habits, relationships, patterns of behavior. Let me share something: two months ago I made out with another woman, not my wife. Strictly PG stuff, I tried to bury it, said to myself, no big deal, won't happen again. Panic attacks begin shortly afterwards: driving panic, excercise panic, heat panic. Took two months to recognize and own up to this no-brainer. Confessed last night, and it's going to be a long road out of the doghouse, but I also feel more whole and calm today. Went for a run that was impossible for me earlier this week. Now the key is to focus and re-commit to my committment to my family. Anyways, I'm not suggesting that you've got issues like me, no. I'm also not suggesting that one thing is the keystone to your anxiety, no. And it's not like I'm cured, no. I still don't know if I'll be able to drive when work starts Monday, but something tells me I'll be in a lot better shape. Anyway, good luck to you, you'll make it. Let me know how it's going.