What can I do to get rid of my feeling of guilt about using household items and my saved money, after I saw my father open the door for me late during his working hours?

This question stems from waswasa (whispering doubts), as there is no connection between the father opening the door during work hours and the questioner forbidding upon himself what was mentioned. If the father is late for work without a valid excuse, this does not render his entire salary unlawful. Rather, only the portion corresponding to the time he did not work becomes unlawful for him. Furthermore, it is not forbidden to deal with a person whose wealth is mixed with unlawful earnings. Therefore, there is no sin upon the questioner in benefiting from his father's money, despite his tardiness for work. He should also be advised to disregard these waswas and to cease dwelling on them.