I made an error on a report that was sent to senior leadership; I discovered it after they had received it. I haven't told anyone, not even my boss, and I'm not sure how to handle it now. It's got me really anxious -- what do you suggest?
Make a plan to own up, but be sure to include solutions for this time and preventive steps for the future.
The inner game
To think this through, first get your emotions under control. Take some deep breaths to calm down and get grounded. Once you're more relaxed, you'll be ready to process this thoroughly.
Before you take any other steps, let your boss know. If this is a hot item it will need to get escalated sooner rather than later, and your boss will be in a position to know that. If you already have corrected information, bring it forward as part of your conversation with your boss. If you don't, let him or her know that you are working on a plan to provide it and processes to prevent this issue in the future.
Then, start your analysis. Ask yourself "what's the worst thing that could happen?" and "how likely is it?" In general, unintentional errors are not going to get you fired, especially if you bring them forward rather than hiding them. More realistically, you'll be facing some awkward conversations and perhaps a higher level of oversight while you rebuild your leadership's confidence in you. Visualize ways that you could manage these situations to build your readiness to face them.
Then consider the impact of the incorrect information. Focus on decisions that may have been made or actions that may have been taken. To the extent that you can, identify ways that you can prepare your leadership to be able to mitigate the effects.
Finally, evaluate the work processes that you followed that led to the error. It's essential that you can provide specific ways that you'll prevent errors like these in the future.
The outer game
In order to move forward, you need to know the causes, so do a root cause analysis, looking into the circumstances that led to the error. It may have been haste driven by short timelines or high workload. It may be that your team has not put systematic checking processes in place. Whatever it is, understand it and build a plan to change it.
This will not be a step that you can do alone. Involve your boss, teammates who may be involved (or need to be in the future) and other colleagues who may be able to contribute to the discussion.
Once your preparation is complete, work with your boss on the proper steps to share the issue, outcomes, and next steps with senior leadership. You may or may not need to be involved, but be ready, and focus on maintaining your confidence in your ability to handle this situation.
The last word
Come clean about the issue, involve your boss, and be solutions-oriented. Everyone makes mistakes; if you handle it professionally, you're likely to have a successful outcome.