Have Quit For 3 Days, Feeling Physically Sick-PLEASE HELP!!!

Hi just found this site and thought it would be worth registering.Having read "The Easy Way to Quit Smoking"-Alan Carr, whilst holidaying in Cyprus last 2 weeks, both my girlfriend and I have quit smoking for 3 days, after countless failed attempts over the last 12 years!! The book is inspirational.Feeling very positive,quit smoking, although going through the "cluck" so to speak!!!Problem is, I cant understand why I keep getting bouts of intense nausea,Herbal cigarettes, every so often.I understand the lightheadedness, caused by the extra red blood cells, but especially after I eat i keep feeling sick. Would be very grateful if someone could explain why and offer any advice.Many ThanksMatt