You probably had covid so see if you can get a antibody test but don't rule it out if you test negative. You can weigh the likelihood of this based on prevalence in your local community and if you know anyone who had covid and how your social distancing was in March.

Also get a pulse oximeter and ask your doctor for one of those lung function devices aka an incentive spirometer (you breathe into them). Get a normal pulse ox when you feel ok and when you have shortness of breath, take your pulse ox again.

There is also evidence of chronic fatigue syndrome caused by covid.