i'd have to recommend talking to your gp about your hair loss also. it may be a health issue that's correctable thru diet. if not, you might be eligible for using rogaine, or another hair restorer. based on how you describe it, i don't think it's normal to lose as much hair as you are.
i was worried about my hair loss, and what i did was collect all the hair i could, that came off during one day, including shedding on my clothes and what came out when i washed/conditioned my hair and then later blow-dried. then i took that one day's worth and brought it with me when i talked to my doctor. i wanted him to see exactly how much it was. turned out it was just normal hair loss, and it seemed like a lot, because my hair was long... just shy of my waist.
it's certainly better to know than to worry.
ps: i'm 38