Hello, I am a biology student and I just wanted to make sure with a healthcare professional. I do not think I could be pregnant. I have not had sex in a month and when I did it was the last day of my previous period. I am on a 28 day cycle so I estimate that I would ovalute around day 14, however, he pulled out before ejaculation and even if he did sperm can only live for 5 days in the uterus and I take my birth control daily at the same time. I have recently been under a lot of stress with finals and I took an adderall a week ago. Today I took a pregnancy test because it has been 3 days since I took my last birth control pill to I anticipated my period to start by now, however it has not. The pregnancy test was negative. I used a clearblue test. I have been experiencing dark vaginal discharge for about 3 days and abdominal cramps such as I would during my period. I just do not see any way I am pregnant, yet I do not know why I have not started my period yet.