Password changed suddenly

Hello! I have a macbook air 2019, i never had any problems with it until now. I was in the middle of creating a new login passcode and it required me to type my current one. So i did, but it said incorrect. I could not type a new password unless I typed in my current one, so I retyped but still got the same result. I decided to restart the mac because I was sure i typed it correctly. When I input my log in passcode, it also said incorrect. I swear did not click on anything, or made any updates on my password until now. So now I can’t access or log in into my MacBook.

[Re-Titled by Moderator]

Original Title: Password changed suddenly