My last period was last Jan.24, 2013. Usually regular, 28 days sometimes 31 days cycle. I should be having my period last Feb. 21 but I didn t. Had a spotting on Feb. 23-27, almost a light period and I thought it was my period but it is so light. I ve been having abdominal cramps , nausea , headache and lower backache . Did 2 HPT and were negative. Am I pregnant?