Miscarriage scare

I ended up having a subchorionic hematoma (hemorrhage) yesterday and am scared to death that it will result in a miscarriage. The doctor said this was common. However, I nor anyone I know has ever heard of it due to pregnancy. This is to include family/friends in the medical field. I guess when the baby attached it created this blood pocket that ended up rupturing. Yesterday I for sure thought I had a miscarriage and went into the doctor. They told me it only slightly increases miscarriage chances, but to just not be very active. I don’t have to be on bed rest, but can only be very slightly active. This is my first pregnancy so I scares me that there is about a 30% chance if miscarriage already. Has anyone else had this or even heard of this before? I am not sure what I should do. The cramping is painful and I am still slightly spotting from the now open wound where it hemorrhaged.