My wife and I had covid a few months ago. It felt like a cold. Chills for a few hours, then sinus congestion and fatigue for about a week, gradually tapering off until it was gone. Start to complete recovery was around two weeks. My wife's experience was similar.
A month afterwards I wondered if the "cold" could have actually been covid so I got a test kit and checked. Yep, it was.
Natural immunity is king.
You had the flu.
I wonder if yours is a case where the test read positive because of fragments of a non-COVID virus were detected? The false positives from over-magnification we've heard about.