The first thing I came to realize was that not every single strand of hair that had come out of my head was due to breakage - some of it was actually shed hair. The basic rule of thumb is that if the hair that has come out is long and has a white 'bulb' on the end then it is shed hair, if it's shorter then it's hair that has broken off mid shaft or at the end of the shaft.
Our hair goes through 3 basic growth phases: Anagen (growth), Catagen (rest) and Telogen (shedding) and all 3 occur concurrently (or simultaneously), so one strand maybe in the Anagen phase while the next strand might be in a Catagen phase.