Suggest Treatment For Nicotine Withdrawal Symptoms

I am a smoker for long. I suddenly stopped this addiction considering it was found in my xray result that I have pneumonitis during my pre-employment medical examination. I am suffering the withdrawal symptoms like insomnia. How can I manage this nicotine withdrawal symptoms. Is taking meth could be of help? I am 38 yrs old, 5 7 tall and 75kgs in weight.