First, check your calendar - do you have any meetings on your calendar (especially all-day meetings) that could be categorized as "out of office"? For example, did someone invite you to their OOO event? Or did you leave a note to yourself in your calendar that someone else will be out of office? Click on the events to check their categorization.
If you find an event that is categorized as OOO when it shouldn't be, the easiest way to correct is to change the event category to a different category than OOO, such as a Hold or Other, or remove yourself from the event invite if it's an OOO event for your colleagues. You can do this by clicking on the event in the Clockwise Planner view.