Anyone feel pressure and tightness in the lower abdomen while BD'ing during early pregnancy?

My tests are negative, however I've been feeling pressure and tightness in my lower stomach- especially when BD'ing. Also have sensitive nipples, but not really sore breasts like most do. I've had some cramping and pain in my back, but nothing too worrisome. I've also had some nausea here and there. Has anyone else felt these symptoms and wound up being pregnant??