I am having the same problem! I just installed WP yesterday, and today I was adding a couple of users, and then all of a sudden, it logged me out and the wp-admin login page has no CSS plus it won’t let me login! I can’t get into my dashboard.
Its affecting my blog page as well. Same thing. It’s a brand new page so there is only the Hello World post right now. Anyway, if someone can help me, I would appreciate it! Here is a link to my blog