Ever since the pediatrician diagnosed brain bleeding in my son, I have been a nervous wreck. What does it mean?

Hard to say. Early in the development of CT,I recall a report that up to 3 % of otherwise normal vaginal newborns had small areas of bleed suggested by the study.Today's studies are more accurate and I suspect your doc is describing a more worrisome event. I have patients that grew up to be intellectually normal with minor motor problems & some that did poorly.Treatment in early childhood helps improve outcome.
Brain bleed in kids. Brain bleeding in children or adults is always serious. Depending on the location and speed at which bleeding occurs will determine outcome to a great degree, ultimately the cause of bleeding must be discovered for this often determines long term prognosis. Surgery is necessary if there are progressive signs of neurologic deterioration.