I also think (and hope) it's related to sodium, at least partly. I've been taking an adaptogens herb formula for those 2-3 months as well. The formula contains licorice, which raises blood tension. If you have an herb that raises blood tension and heaps of sodium plus stress in your life (corticoid hormones messing the Na/K ratio through the kidneys) ... well ... I don't think that's good.
Hypertension can damage the kidneys. I don't think 3 months of hypertension can damage them very bad, but still... I never ever in my life had kidney problems and the onset has been very quick. I have appointed a visit to the doc on Monday. Will report once I know so there's a record for future use.