my password is being changed without my consent...

7 days ago, I tried to log into wordpress.org, got an error message saying my password was incorrect. I did not change it, nor did I authorize someone to change it.I submitted request for change of password, using my email address and was able to change my password. Today, the same thing has happened and again, I was able to change the password, but this is not a good thing. Any ideas? I think perhaps changing my username would be a good idea. I am confused about doing that. In the USER area, for Generate Press, it says that username cannot be changed. But I see on Youtube, I can change it by adding a new user. I am a newbie. I am confused between having a Generate Press username and password and having a wordpress.org password. Any help on this ? Thank you so much ! I did hire two web guys in the last month and gave them my usernames and passwords. Maybe I should change them all ? They seem honest and did good work for me.