What Causes Loss Of Memory After A Head Injury?

I am 62 years old. When I was 10 yrs. I fell off a small building and hit my head on a brick. I can't remember much about the accident but I was bleeding and my brother took me to the doctor. In those days in Georgia, it was much prejudice and the treatment was sewing the womb. That's all I remember. I have been having symptoms for years. For example, headaches, numbness but the most noticeable is when I talk people often ask me what did you say. It seems as if I say something I don't mean to say, and I don't know I said it. My sister told me last night that I jump from one subject to another. Maybe I am saying something that I don't know about. I have a job and I have two degrees but I believe that the old head injury are reasons I can't remember past history.