4 Answers

Why as mine fallen out

Use conditioners and don't pull your hair back with a rubber band, that breaks hair. Also, don't brush your hair when it's wet, use a comb instead........

You might need a good trim.....if it's long and fine it tends to break even more easily than other hair types....I know as I have baby fine, somewhat thin hair and it breaks easily....I'm no child either and I have had this problem all my life....good trim (if affordable) every 6-8 weeks helps a lot. I learned how to trim my own out of economic necessity...ditto about the rubber band answers...always use elastic coated ones!

If your hair is long do not use a brush to brush it out while wet, use a large tooth comb and start at the bottom and work your way up to the top.  Also, as jhharlan said, don't use rubber bands, just use elastics that are cloth-coated. Could be your health/diet, as well.  Perhaps some medications, too?