Thanks again for providing a new source of good information that can help me to understand this issue. Steemwhales was not familiar to me.
The fluctuation in the reported value of my account reflects accurately my confusion over exactly how badly that trade failed, and why I had to estimate a very wide range of potential loss.
Ultimately, what I learned from this experience is that I shouldn't expect to profit from trading activity without good understanding of the underlying mechanisms, and good data, both of which you have raised.
Thanks!