In the US, companies are not required to give severance packages when doing layoffs. Check your local states' labor laws, as it may differ, but most states simply follow Federal Guidelines and there isn't a Federal requirement.
The federal Worker Adjustment and Retraining Notification Act (WARN Act) requires employers to provide 60 days' notice, during which all wages and benefits will continue to flow as usual, giving those who were laid off at least a little time to brace for unemployment, or get busy finding that new (better — knock wood) ...
If you're fired for cause, which it sounds like you will be, then they don't need to give you severance. Normally companies will give something to avoid getting sued for wrongful dismissal, because normally there are steps they need to take in order to avoid those kinds of lawsuits.