Bleeding at 25DPO after BFP and ultrasound

So I woke up this morning (at 5weeks 2 days and after seeing gestational sac on ultrasound last week) cramping and bleeding. It’s been light and dark brown for the most part but constant. My OB was off but I was able to see one of her colleagues. After a very long morning, today’s ultrasound showed the gestational sac and yolk sac still intact. The Dr didn’t seem too worried and told me to come back Thursday morning for a recheck. Thankfully my OB will be back in the office by then. Since the appt, cramps and bleeding have not eased up. I’m scared to death! I would love to hear stories from those who have experienced anything like this. He mentioned implantation bleeding, but shouldn’t it be too late for that? Any insight/ prayers would be appreciated!!!