Site not displaying correctly and cannot login.

Hello all.

I have a WordPress site that was working fine. Then suddenly the page starting displaying incorrectly and I could not login. When I tried to go to mydomain/wp-admin it would redirect me to the main page. So I tried going through wp-login.php and it would let me enter the username and password but then again it would redirect me to the main page.

my site is https://www.underwaterwaterproofcamera.com

Any help would be greatly appreciated.

Scott