spotting

Hi mommies! I'm 5w 3d with baby #2 and I've been spotting for the last 4 days with mild cramps 😕. It's not heavy but it's been consistent and goes from brown to red to dark and clotty. I had an ultrasound today and there was no heart beat but the dr said it could be to early. It was weird because the baby was measuring at over 7 weeks and I'm only 5. Has anyone else had anything similar to this and miscarried or been fine?