My period lasted only three days but only one was normal the other two were really light I can feel a pulse in my lower stomach my mom had her period for four months when she was pregnant with me could I be pregnant

While you won't have an actual period if pregnant, you can have some spotting or bleeding.

Sometimes there will be a "period" that is off from the norm in early pregnancy. Shorter in duration and/or lighter in flow. The pulse you would feel is your own.

If you think pregnancy is possible, try a test. It could just be an off period, so if you get a negative, give it another week or so and try another test. If still negative, wait and see what happens when your period is due next month.