Should I be worried?

Friday afternoon I had my first transvaginal ultrasound at 6 weeks and 1 day. They saw the yolk sac and embryo (the heartbeat was a little slow but I don’t know the exact number). Friday night I started having some light brown discharge which has not stopped yet. I have had some cramps (nothing severe except one short sharp pain this morning) throughout the day today. I am 6 weeks and 3 days today. Should I be calling my doctors office? This is my first pregnancy and I’m terrified.