Roughly 2.1 million people in New Jersey have tested positive for the coronavirus or one of its nasty variants since the COVID-19 pandemic began here on March 4, 2020. Since then, residents have been bombarded with messages and advice, both good and bad, about prevention, getting vaccinated and quarantining, once a person tests positive. But what can people who’ve had COVID expect now that they are recovering or have recovered? Can you get it again? Do you have stronger antibodies and increased natural immunity? Why are some symptoms hanging on? I was diagnosed positive after Christmas, despit…