Brown spotting....help?

Has anyone had an implantation bleed seen on ultrasound turn into brown spotting later in the first trimester? I’m 9w4d and am experiencing brown spotting, very light, only when I wipe and not on my underwear.... I went up to emerge last night because my anxiety when through the roof because of the spotting. I was told sometimes it comes out and sometimes it doesn’t... they did an ultrasound and I got to see baby, much bigger than only a week ago which was reassuring with a very strong heart beat. The doctor said that brown is fine and indicates old blood. He also said that at this point in pregnancy my risk for miscarriage is so low, not zero but very very low, that it isn’t something I should be worried about.

Im just wondering if anyone else has ever experienced this?