SCH subchorionic hematoma

I had my 20 week anatomy scan 2 weeks ago and the doctor just ordered a follow up scan for me saying that she saw a shadow behind my placenta which could be a blood clot. She also mentioned it's almost nothing to worry about. My follow up is tomorrow but I'm so freaked out that I can't concentrate on anything. Have been googling ever since and finding that it's more concerning in the second trimester. Anyone gone/going through that in their second trimester?