Completely locked out of site

I have installed wp with no problems and had it running for about 3 days.

I looked on my site and saw there was only 1 link in my nav bar so I went to check the pages section in the admin page to see if the problem might have been there, but when I clicked the link, the wp login page came up.

I entered my user and password and it has repeatedly told me that my username is invalid. I’ve tried logging into PHPMyAdmin and it still doesn’t work.

Even when I click the “lost your password link” it doesn’t recognise my email.

Really need help with this 1, thanks.