False pregnancy i suppose. Hi my name is Brittany im 18 years old. My boyfriend and i have recently become sexually active. Im on the shot and we have had some cases where he has not worn a condom. It always leads me to believe i could be pregnant, although all the tests are negative. I seem to have some of the symptoms of a pregnancy but never am actually pregnant. Some of these symptoms are- throwing up, fatigue, excessive weight gain and breast tenderness. All these show up pretty fast. Do you know why? Also after sex the next day i get a major stomach ache usually on my bottom left i believe. It sometimes lasts for days I also have no idea why this happens. Thank you for taking the time to read this and help me out.