I had unprotected sex the Thursday of my period week. I am on birth control but missed two/three individual days in my pack; Two of them were my last two days of active pills. I just skipped them and started my period (placebo pills). I took plan B about 20 hours after having sex. A week later I was feeling nauseous and lightheaded and slight cramping. I have started taking my birth control last week again, starting Sunday and it now the following Wednesday (week 2 of birth control). I am now having pain on my right side, like under my rib cage. Is this a common symptom, or could I be pregnant? I took a pregnancy test this past Monday and it was negative. I think it may have been two early (two weeks til my period and 10 days after sex) What is the earliest I could take another pregnancy test? Do I have to wait another week or two to take a test? What are my chances of this being pregnancy?