... pharmacist said it may take a while and gave me the 1/20 instead. that was about 2 months ago and I missed my last period completely. I am now about 3 weeks late. ive had bloating, but no cramping like usual. some mornings ive been slightly nauseated and dizzy but I brushed it off as maybe being sick. could lowering my regular dosage for a month decrease its effectiveness in preventing pregnancy?