Get back into an account that has stopped accepting your password, without creating a second empty one by mistake.
The password that has worked for two years is refused, and the mind goes straight to the worst explanation. It is almost never that one.
Everything that makes this straightforward has to be set up while you can still get in. That is the one unfair thing about it, and it is worth an evening.
Key points
Use Forgotten your password rather than making a second empty account
Get a code to an address or number you still have
Sign everybody else out as part of setting a new password
Set up the recovery details now, while you can still get in
What to remember
Forgotten your password is a front door, not a back one. It is the route they built for this.
Get back in first, then look at Recent activity. Guessing about it from outside helps nobody.
Try this
Open the security settings of your main email account tonight and read the recovery email address and phone number they hold. If either is out of date, that is the ten minutes that will save you an afternoon one day.