Can you give me some idea of Dissociative Amnesia description and symptoms? I think I have mental problem. Please help me?

Yesterday I had a talk with my mother about things from my childhood that damaged me. Some were things she wasn't aware of and other's were things I wanted validation for or an apology. She came to my house at 10am and stayed until 6 pm. I remember putting together soup for lunch, I remember opening the back door..... I remember her driving away... I do not have a single memory of talking to her. Not one. There really are no other symptoms of amnesia... it is simply the loss of memory that is unusual and can not be accounted for with an illness or injury or drug use, etc. I am also missing 5th grade. I remember kindergarten... I remember all other grades (at least some of) but 5th grade has been completely wiped from my mind. I don't remember my teacher, the school, literally nothing. I have other periods of time that are missing... At one point I lived in Florida and the next I lived in Massachusetts. I had a home and job and everything.... months had passed. If you think you have a mental problem then you need to see a doctor.