How to log into my self hosted wordpress site?

I have been succefully logged into my dashboard to add more posts to my self hosted wordpress site. I installed wordpress on my host and it worked fine. I hadn’t logged on for around 6 weeks and now my admins site would’t show up anymore and my details don’t work anymore if I want to log into my dashboard. If I want to go directly to my page (www.bettina-john.com/admin-wp.php it says:

Not Found

You tried going to https://www.bettina-john.com/admin-wp.php, and it doesn’t exist. All is not lost! You can search for what you’re looking for.

Anyone an idea?