Just wanted to give some hope and update for those who have been diagnosed with a subchorionic hematoma. I was diagnosed at 8 weeks with dark red spotting and a little bit of clots. It was 2 cm at the time as has already shrunk to half size (little less that even) in two weeks with no bed rest but no exercise or sex (i do work in an inpatient rehab hospital and still had to help transfer people and also did go to disney for 3 days with lots of walking). The us tech said she had to look hard to even find it and my doctor said I can return to the gym!
So try not to let it stress you out too much. Think of it this way, we get a bonus ultrasound! Things will be okay!