Cramping in lower back and abdomen?

Rachel
Hi all. I'm a little bit worried because this morning I'm having some cramping, especially in my lower back and lower abdomen. It feels kind of like menstrual cramps. I'm also having just a slight bit of brownish discharge. I should also probably note that this is around the time I would normally get my period. Has anyone had this or have any idea what it might be? Should I be worried? I'm 13 weeks today.