Pregnant despite taking the pill?

I've been taking the pill for 18 days now. Since the first day of my period, every day at the same time. I haven't taken any other medication, and I haven't vomited. However, for about a week now, I've had strange symptoms. I feel very nauseous every day. I'm also extremely sensitive to smells and have abdominal pain. I've already been to my regular doctor, but nothing was found. I also called my gynaecologist. However, he said I should wait until my withdrawal bleed and then come in if that doesn't happen. I don't know what to do. Has anyone else had similar symptoms? Or could these be side effects?