Maintenance Technician reported not replacing the oil cap and leaving a screwdriver in the oil filler compartment.

Narrative

I am submitting this report to voluntarily disclose a maintenance error that occurred during routine servicing of an aircraft and to ensure the circumstances are documented for safety review and corrective action.Event DescriptionWhile performing oil servicing on the aircraft; I inadvertently left a screwdriver on the oil service panel door. After departure; the aircraft flew with the oil panel door open.The condition was discovered after the aircraft had already departed. The event resulted in an open oil service door and loss of oil due to the displaced oil cap. No damage or injury occurred; but the potential risk was significant.Once the issue was identified; appropriate notifications and corrective actions were taken per company procedures.Root Cause and Contributing FactorsThis event was the result of a breakdown in tool control and final area inspection. I did not properly complete a tactile and visual tool check before closing the oil service door.At the time of the event; I was experiencing significant external stressors that affected my focus and cognitive workload. These included:• A rapid and stressful residential move due to the risk of homelessness• My father experiencing a second hip implant rejection with a subsequent bacterial infection and surgical complications• My fiancée undergoing a difficult recovery from back surgery• Ongoing transportation and financial stress; including having no current car insurance or license plates while my vehicle was parked on the streetThese factors contributed to fatigue; distraction; and degraded situational awareness consistent with recognized human-factors hazards particularly distraction; stress; and pressure.Due to lack of available time off and financial constraints; I was unable to remove myself from duty despite these conditions.This was not an intentional violation or negligence but a human-factors-related error caused by a lapse in tool accountability and final verification under elevated stress and cognitive load. The event highlights the vulnerability of maintenance tasks involving panels; caps; and tool use when mental bandwidth is reduced.Eng 2 oil door has screw driver in it and 2 screws missing. Crew reported didn't notice on pre-flight.