i have this thing where when i'm nervous i pull my hair out. i only pull out one hair at a time but after a while it accumulates and now i have to wear a hair piece. i also eat the hairs after i pull them out. i don't know why i do this but it's hard to stop.
There's a lot of information on the net about this. Try starting with a Google Search - "Hair Pulling" and that should point you in the right direction.
Alternatively, you could try your country's National Health Service Website.
Good Luck.