Need to quit smoking right away!

Hi, I'm just at my wits end right now. I've been a 1/2 pack to a pack a day smoker since I was 20..I'm now 40. I have not been feeling good for many months now and have had a dozen medical tests. Including a very intense complete cardio work up. All my tests have come back normal except I have some sinus tach which is benign. I also get palps from time to time. So, My cardio doc will not do a thing more until I quit smoking. I think he thinks the smoking is the cause.I'm afraid I have a heart condition even though right now things look fine. I'm thin,smoking cessation, I excercise 5 days per week,stop smoking now, eat very healhthy and I don't drink. But, I'm afraid to give up my last crutch in life however,I want to live so I have to. I'd like to go cold turkey. Want to know how bad that is? I'm afraid to wear the patch, chew the gum because I'm afraid it will give me palps and they freak me out. Now as strange as this seems I'm afriad I'll die from the withdrawl.. and that's what keeps me lighting up. How do I get past that feeling and will I die? Also I will not take chantix. Someone please help me.