Don't take this the wrong way but you appear weak. I hope you didn't include anything about your family in that letter either. Never tell ups any personal info, they WILL use it against you. Iv seen it first hand. Iv been here many many years. The fact that you keep stressing how important this job is to you and your family is a terrible thing to do.
I act like this job isn't
to me and always talk about all my "riches" To managment. You can't exploit somebody who doesn't appear to need their job.
You made a mistake it happens brother. I have made big mistakes.
The union will have your back. I honestly would expect you back in a few weeks at most at the local level. I doubt it will go past that
Best of luck, you make the job.... don't let the job make you