To start I quit smoking 6 weeks ago, at first I experienced some constipation , I was on chantix , and experienced some abdominal cramps . I stopped the Chantix two weeks ago, now for the past week, I have had a severe headache over my left eye, constantly tired and then began vomiting what appears to be white foam for the past two days. Any suggestions on what it could be, I have not been running a fever.