I need help with my email

Hello,
Every time I try signing into my email it tells me I have the wrong password or that my email is not right. And I know my email and password for sure but I think somehow it changes by its self and then I forgot all my security questions is there a way I can update all my information but still keep the same email I don't want to have to change it I have very important messages that I received in that email for years.