Has anyone been told they have a Subchorionic Hematoma?

Im 7 weeks, 5 days. I went to the ER yesterday for "chocolate brown" blood. My vitals were fine, levels all where they need to be, baby fine with a heartbeat of 150bpm. The only thing that the doctor was concerned about was a subchorionic hematoma. He didn't explain much, honestly he acted annoyed with me. Has anyone ever had this? What was your outcome? Did it go away on its own? Just want peace of mind. Share your stories. Thank you!