In truth I was about to ask with reference to your question ... "Are you on drugs...?" .... Apparently yes you are.
Hair is interesting stuff, in criminology it possible to trace what people have ingested and when for months previously. There is therefore a sound reason why they choose to test hair rather than urine or blood .... Drugs leave the blood, fake urine can be used .... but hair, now that is 100%.
As other people have said .... why the hell are you taking drugs if you know you have a test coming and it is 'so important'
Real loser behaviour sonny.