My reactions were normal (perhaps not typical) physical withdrawal symptoms:
Diagnostic Criteria (Nicotine Dependence)
1. Nicotine abuse: A destructive pattern of nicotine use, leading to significant social, occupational, or medical impairment.
2. Must have three (or more) of the following, occurring when the nicotine use was at its worst:
1. Nicotine tolerance: Either need for markedly increased amounts of nicotine to achieve intoxication, or markedly diminished effect with continued use of the same amount of nicotine.
2. Nicotine withdrawal symptoms: Either (a) or (b). (a) Two (or more) of the following, developing within several hours to a few days of reduction in heavy or prolonged nicotine use:
* sweating or rapid pulse
* increased hand tremor
* insomnia
* nausea or vomiting
* physical agitation
* anxiety
* transient visual, tactile, or auditory hallucinations or illusions
* grand mal seizures
(b) Nicotine is taken to relieve or avoid withdrawal symptoms
(source: psychologynet)
There are other sites as well. Just don't have the time to go back and find them all.
I just had really bad withdrawals reactions, probably because I went cold turkey after 29 years of smoking and a year of smoking two packs a day. I was vomiting the second day and having heart palpitations the second and third days.