Subchorionic hemorrhage

Hello mama, I am 12 wk 3 days and heavily bleeder last night , had to wear pad . My 1 pad was fully soaked in an hour ani others 2 were ok . Went to Er they did a blood test and ultrasound transvaginal and from up both ways . Baby is fine . Heart rate is 142 bpm. They told me I have subchorionic hemorrhage . Gave me a paper about it and discharged me around 2 am . Please help me to know about it. What should I do and don’t? What are my restrictions? How careful I must be ? Do I have to bed rest? How long this will be here ? I am so worried and helpless. First time going to be mom. I don’t want to loose him 😭😭. Please help me