Login went AWOL

This afternoon I tried to log into my WordPress account using a desktop computer. I tried twice with the known email address and once with the known username, but could not log in. I then tried using my laptop. Since the password had been saved on my laptop I couldn’t check it against what I had used on the desktop but I could change the password. I did that, logged off with the laptop and went back to the desktop. Log on failed again, even with the new password. I tried “lost password” using my username, and had a message on the screen claiming a message had been sent to my registered email address, but nothing arrived, though the advice that I had changed password on my laptop did arrive. Trying “lost password” again, but using my registered email address resulted in a message that there was no record of that email address. I tried logging on with the laptop and the new password, but even that failed. I needed to log in using the desktop so that I could install Jetpack, so I created a new username to get onto the WordPress site. Several hours later I logged onto the WordPress site using this username and the new password I had created during the afternoon.
What on earth happened?