First off: The myth of ascorbic acid causing kidney stones has long ago been debunked [and, in fact, the very opposite has been found to be the case].
Secondly: Ascorbic acid is a powerful internal cleanser. My advice is to never completely stop ingesting it, but to moderate one's intake depending upon the detoxification symptoms one is manifesting, i.e. ingesting more [up to Bowel Tolerance] when one is feeling reasonably well, and less when one is feeling too uncomfortable.
Also, Margo, ideally your daily ascorbic acid dosage should be divided up into as many doses as is practicable, i.e. vs. ingesting the whole day's dose at once. As an example, I ingest mine in 10 to 15 [divided] doses per day.
I hope that helps, Margo. And by-all-means, if you have any other questions, comments, and/or concerns [about ascorbate ingestion], I hope you will post them here [and/or please feel free to contact me privately].