Yes, this was attack to your site. I recommend you to block user after 3 failed logins for at least 2 hours. It will not block them to try it again, but at least stop spamming you...
Also consider to combine Wordfence with other security plugin. The reasons are following: Wordfence support activity is zero, logs are mostly useless especially in case that there is large number of attacks in short time and finally Wordfence is only active protection. Other plugins also provides passive protection with many preventing settings.
Have a good day
Pavel