If i am sitting down and can visibly see some pulsing through my abdomen when my heart beats, is that abnormal?

Not necessarily: If you are thin, you can feel (& sometimes see) pulsations of the abdominal aorta (big artery below the diaphragm) in different positions. The problem comes about if the aorta is enlarged. That can be diagnosed by a skilled doctor on exam (if you are thin) but is more often diagnosed by ultrasound, which can measure the size. See your doctor especially if you have pain, bruising, bloody stool or S