Jon, so sorry to hear that you have been very sick.
Covid is nothing to screw around with. My mid-30's daughter got a mild case right at the beginning of the New York outbreak and has been sick ever since with Postural Orthostatic Tachycardia Syndrome. POTS results from damage to the autonomic nervous system: blood vessels in the extremities stop responding properly by contracting when one stands up from sitting or lying, kinda like the transient dizziness we sometimes get from standing up too fast (Postural Orthostatic Hypotension). In this case, it causes the heart to race in an attempt to get the blood back up: her heart rate goes from 60 to 140 in seconds just by standing up, and this leads to chronic fatigue and relapses after even minor activity, like a walk around the block. There are treatments but no cures, and the long term prognosis is not known. POTS is more common in young women, but if even a mild case of covid can cause such damage to a healthy young person, the possible consequences for old farts like most of us can be grim.