OK, folks. Schutt alerted me to the probable cause of all this and that is my Protection software, or actually, what I put into the software. Seems that I used the minimum number of digits required (4) of a credit card number to trigger an alert, not realizing that within the thread's normal use of userid's I might get a match and trigger the alery. This seems to be the case as I have had the same thing happen now at other websites.
Strange in that, I've had the Protection module active for about 3-4 weeks and haven't had a hit till last night and then again today.
Anyway, that seems like the probabl cause and that it is NOT a malware attack by anyone.
Sorry, if anyone got annoyed or unnecessarily concerned. My motivation was only to protect others from what I thought might be a serious problem.