Admin panel unaccessible?

I will try to explain what happened to me a few hours ago. Been looking for a way to solve this without any luck so far …

I had my new blog up and running at https://www.forumnet.be/verduyckt with admin panel at https://www.forumnet.be/verduyckt/wp-admin.

In the General settings the WP address (URL) was https://www.forumnet.be/verduyckt/ as was the Blog address (URL).

I’m also using an URL redirect to have my domain name https://www.verduyckt.be point to my blog. Now, for some reason I changed the WP address (URL in the admin general settings from https://www.forumnet.be/verduyckt/ to https://www.verduyckt.be and clicked update …

I haven’t been able to login to my admin panel since then … ??
Seems like my admin panel does not automatically recognise me anymore as the admin and always asks me to login or register. Admin username and password unsuccessful …

Anybody knows what has happened?