BibTeX:
@incollection{Various,
  author = {Various},
  title = {In reading over my diaries - so very little of which I have quoted},
  booktitle = {bahaistories.com archive},
  url = {https://bahaistories.com/subject/anxiety},
}

APA:
Various. In reading over my diaries - so very little of which I have quoted. In *bahaistories.com archive*.

MLA:
Various. "In reading over my diaries - so very little of which I have quoted." *bahaistories.com archive*, n.d..

Chicago:
Various. "In reading over my diaries - so very little of which I have quoted." In *bahaistories.com archive*, n.d..