Depending upon how long the infection persisted, I think Covid is still possible.
A friend of mine almost certainly had Covid “in the household” early in lockdown. All three people had pretty compelling symptoms, one still has no sense of smell or taste. My friend seemed worse than the others but soldiered on for several weeks before seeking help. By that time she tested negative for Covid but needed antibiotics for a bacterial infection. Speculation is that she did have Covid originally, which triggered the bacterial infection, and then the Covid the got better, leaving just the secondary bacterial infection.
I know at least one other person, a guy in his twenties, who needed antibiotics for a secondary infection after getting relatively mild Covid.