Password Reset link invalid

Hi,
I have a wordpress site that has been set up for some time and recently I can’t log into the admin panel. It says password invalid. I’ve tried all of the passwords and none of them work. So I clicked on the forgot password link. It sends a reset password link to my email address. But when I click on that link, or past the link into my browser or carfully type in the link it gives me a “this link appears to be invalid error message.” I’ve tried this several times and it just doesn’t seem to give me a valid link for resetting the password.