I pill taken on june. Withdrawal bleeding occurs 10 days after I pill. Then period came after one month of withdrawal bleeding but lasts for only 2 days. And now second month period has came but this also lasts for only 2 days. Pregnancy test shows negative 6 times. Does I pill cause this side effect. Period length has refused to 2 days only and usually 5 days. What to do. Very concerned about my girlfriend.