Hi, we had unprotected sex on 22nd Dec, within in three hours i consulted a doc and took Postinor 2. My next period starts on 3rd Jan. Since 28th I am having some mild cramps in my lower part of tummy, doc told me that i should be expecting some change in period cycle. I took a home pregnancy test on 30th Dec, and it was negative. Are the pains after affects of of Postinor 2 or there are chances of pregnancy ?