Yeah, it’s not too helpful, but maybe they have no more data. If you want to know more, go to https://haveibeenpwned.com/ and enter you e-mail. They maybe know, where your data came from.
Otherwise: Do you have a different and random password for each site? If yes, change your gmail password (in as it was gmail itself) and then watch the news, if a site you use was hacked. If you don’t have different password for each site… Well then you are gonna have a fun day changing all you passwords to new ones. And use a password manager and a new random password for each site this time, please.
These services are so useless. I have about a million years of free “monitoring” from all the data breeches. Whoever decided a year of useless false-alarms was an adequate remedy for a class-action settlement should be launched into the sun.