so everytime I get some bloodwork done my calcium levels seems to fluctuate..sometimes its borderline high and other times its slightly high. But my vitamin d levels remain low

my question is this..is it okay for someone with borderline/slightly high levels of calcium to supplement with vitamin d3? and if so, how much?

I've already tested negative for hyperparathyroidism twice so it isn't that. any help would be nice. thanks in advance!