Confused!

I am 5 weeks and 4 days with my second and went to the ER last night. I was experiencing brown spotting throughout the day, but nothing significant just looked like a bit of discharge going to the bathroom. But then I woke up to go to the bathroom around 11pm last night, and bright red blood came out and a lot on the toilet paper when I wiped. They did a pelvic exam and the doctor said she saw some older looking blood but it wasn’t a lot. She also said my ultrasound looked great, the baby looked fine and hcg was good at 2100 (I don’t know what the levels mean, just that she told me that was good). I’m calling my doctor for a follow up today. Feeling confused. It seems that I am experiencing symptoms of miscarrying, but I have not miscarried... yet I suppose. I have cramping but it’s very light and inconsistent. The ER doctor said to expect the rest of the blood she saw to come out over the next few days and to not be alarmed unless I see bright red again and/or clotting. Resting a lot and hoping for the best. Has anyone experienced anything like this and gone on to have a healthy pregnancy?