Are you really sorry you smoked the pot..or are you sorry they tested you on Tuesday???:uhoh21:
I am also sorry that you have a difficult family decision to make and I am sure that the pot helped ease your pain even if only temporarily. Next time have a martini...with olives of course.
If you are not a cronic smoker the half life of the pot may not stay in your system very long. Cronic smokers it takes up to 6 weeks to clear. There are herbal remedies that people use like "golden seal" which you can get at the local health food store. It is an astringent and with lots of water will clean you out in a few days.
rather than coming clean and "admitting" guilt, perhaps you would be better off waiting, denying the possibility of anything like that being in your system and start imediately flushing out your system in case of a retest. If you are honest you will have to deal with whatever they throw at you. If you deny, deny deny you may get the benefit of the doubt. Of course, they will be spot checking you again so no more lapses of common sense with your future.
Obviously this is a moral delema for you. The truth usually works but in this case the truth could be the end of your nursing career.
Good luck, I hope it works out for you. And many prayers for your mother.