All perfect praise be to Allah, The Lord of The Worlds, and may His peace and blessings be upon our Prophet Muhammad and upon all of his family and companions.
Having reviewed the above question, the Board of Iftaa`, Research and Islamic Studies clarified that the Civil Bureau system is so flexible that it opened a window of opportunity for an employee to have a job after official duty's hours, after obtaining the permission of his superior, in order to improve their income so long as public interest is preserved and no violations are committed. This is because Allah, The most Exalted, said(What means):" O you who believe, fulfil your bonds." [Al-Mai'dah/1].
In conclusion, you(Questioner) aren't obliged to get rid of the money you have earned from your lawful business mentioned above; rather, in the future, you should obtain the permission of your superiors. And Allah knows best.