I am going to take a different approach on this issue.
I think, you should resign from UPS and move on to a different career. UPS needs people with integrity, people who can control themselves and their behaviors.
Your co workers also depend on you being of sound mind and judgement. One stupid action on your part could (in theory) hurt a co worker.
Doing drugs is one of the weakest things a person can do. It signals a real weakness in your character.
I for one, wouldnt want a drug user of any kind working alongside myself.
You should seek treatment, accept your shame in your town, and move on. UPS isnt the place for people with addictions.
Addictions lead to other things, like theft, you are already dishonest and this by way of arrest.
Find a better way to live your life. Find the strength to become an adult free of dependancy.
If not, you are doomed to repeat your mistakes over and over until you commit a more serious crime and then your next job may be punching out license plates.
That is brutally honest.
TOS.