I started birth control on Aug. 5th.. Then I had wisdom teeth operation a week later and was put on antibiotics to treat an infection I had in my mouth. The Tuesday after I had my teeth out my boyfriend and I had sex. We usually do the pull out method. Well the Sunday after I spotted for about 4-5 days so not sure if that was my period cause it has no characteristics of a period. No cramps, no clots, it was bright red, no period odor, nothing. Then two weeks later no period but took a test. Come up negative. A week later no period. Took another test negative. And this week. No period yet. Keep in mind that I have only technically been on the pill for a week due to being on antibiotics. I plan to restart the birth control once my period comes. Is it possible to still be pregnant and tests coming up negative? I have no symptoms what so ever except for cramping.