It would be interesting to see how many of those who thought they had it prior to Feb/March 2020 ended up getting Covid later, as it would mostly rule those anecdotes out.
But it's very unlikely it was Covid, because Covid is much more infectious and more deadly than both colds and flu.
People weren't masking or taking any precautions then, so Covid would have spread very quickly indeed. And that would have created an obvious medical emergency, with hospitals at full capacity and a clear peak in unexpected deaths.
Relatively minor symptoms, no huge increase in hospitalisations, and no huge peak in deaths all suggest Covid wasn't the culprit.