Did you consider the possibility that you actually caught it 2 months ago and not last fall?
There is a huge problem with the theory that COVD was around here last fall. No matter how much "they" could try to hide it the pandemic curve could be seen by many. Look at the rate it escalated in 2 months since it was known to have escaped China.
Regardless, glad you are better and contributing to the herd :-)
McD, Can you be more specific about the blood test?
Was it a specific test to detect the presence of antibody to the virus (SARS-CoV-2) causing Covid-19 or was it a blood test to see if there were any changes in the blood suggestive of an ongoing or recent viral infection? Your answer could be very helpful with a situation which has developed in our locality, an island off the UK.