Hi, Thanks for the query. If you used the contraceptive pills only for 2 weeks, that may not give protection from pregnancy. So if you had unprotected intercourse around the time of ovulation, there is possibility of pregnancy. The spotting you had could be withdrawal bleeding due to stopping of tablets or could be implantation bleeding in case of presence of pregnancy. Urine pregnancy test kits may not detect early pregnancy sometimes. For more details : http://srsree.blogspot.in/2012/05/pregnancy-tests.html So, you better go for blood test for pregnancy. If the test comes negative, consult gynecologist once and get examined. If she recommends go for ultrasound once. By doing ultrasound the possibility of pregnancy can be ruled out and also any other possible causes for delay in periods like poly cystic ovary disease etc can be identified. And also check for thyroid profile once. Then with your doctor s advice you can take tablets to induce withdrawal bleeding. Take care.