A PA28 Pilot reported becoming disoriented on a Runway 5 downwind and landing on Runway 32 without first notifying the tower when he realized his error before landing.

Narrative

Approaching Class C airspace; I was told to report a left downwind for Runway 5 by the Tower. I promptly did so at about midfield. The Tower advised me to continue left base and keep an eye out for traffic that I would be following in. Scanning; I saw no traffic but continued on. I turned base; then final; still not seeing the traffic. On short final I realized that I was coming in on Runway 32 instead of 5; so somewhere between downwind and final approach I deviated approximately 90 degrees onto the inactive runway; hence explaining why I did not see the traffic. I made absolutely sure there was no traffic on either runway before coming in; but did not advise the Tower. I should have broken off the approach and advised the Tower but I did not. In order to make sure I do not make a mistake like this again; I am going back to my CFI for refresher training in airspace operation; pattern work; and general competency with my skills. I will do this before flying solo or with a passenger again.