You should see your doctor about this. You have had some great answers but seriously it is something u should first address with your GP.
Sounds like panic attacks to me, and if you quit they will probably temporarily get worse. However, if you go to a doctor, he will treat the panic attacks and will help you get off the smoking as well. But you gotta want to do it, if you dont then you simply will not be able to do it. It is more a mindset than anything Im afraid.....In other words, it takes balls.....
Trust me I know.
Sorry if that offends anyone, but sometimes you just gotta sum it up in one sentence that people can understand.....:P
It's my guess that it is the anxiety about smoking, and not smoking itself, that is causing the symptoms. If you are going to stop smoking - that's fine. But if you are going to continue smoking, don't make yourself ill by worrying about it.
No mental illness? Have you come up with that diagnosis on your own, or have you seen somebody about your concerns? First off, seeing your regular doctor is a great place to start if you are considering quitting smoking. It is also a great place to seek help with anxiety.... I am no doctor, but it does seem as if you have a bit of anxiety.
Anxiety is treatable.... I am being treated successfully for it right now. Quitting tobacco is doable as well, as I just quit 30 days ago... cold turkey.
With quitting, you have to be 100% committed to the quit. You have to formulate a plan and a doctor can assist you with that.
Go see your doctor.... it is important. Anxiety is a booger but can be beat.