How about career advice?

Taken from the Dept of Labors web site

"If your previous employer gives a nasty reference to a potential employer, you may have an action for a defamation lawsuit. Employee reference laws prohibit employers from defaming a current or ex-employee to a prospective employer. In the employment context, defamation is an injury to one’s reputation or career as a result of the individual’s employer making false statements of fact about them. False statements of fact do not include the employer’s opinion. For example, if an ex-employer tells a prospective employer that "in my opinion, she was an incompetent worker,” it will be hard to prove defamation as this is the employer's stated opinion, and not a statement of fact.

However, if your employer exaggerates your poor work performance or tells prospective employers false, unproven facts about your performance, this may be defamatory. If you were fired because your employer suspected that you were stealing from the company, but this was never proven, the employer is prohibited from passing this information on to a prospective employer, as this would be a false statement of fact. Further, if you suspect that your ex-employer defamed you in order to terminate your employment, you may also bring a wrongful termination action against them."
I am not an attorney. I would suggest you contact one or the DOL.
If you were fired for the reasons you stated, they would have to prove it. I'm sure they couldn't if it were to go to court. So again, consult an attorney, but I would think you have grounds for a suit.
If nothing else, I would have an attorney write a strongly worded cease and desist letter to you're former employer.

I was let go from a job because I "yelled" at an employee. The kid worked for me and went missing for nearly an hour. I guess telling him to get his butt back to work hurt his feeling.

This sounds very similar to filing an EEO complaint against the USPS. Don't know how true this is but I was told that the DOJ is the USPS legal defense. In my close to 20 years with the USPS I know of only one EEO complaint that went the employees way. It only took 9 or so years for it to get settled in court...