wp-admin not loading

I have only been using wordpress for two weeks now (prior warning). I just today directed a new web address to my website and all or a sudden my wp-admin page won’t load, it is just a blank white screen. I have since unassigned one of the web addresses to see if this was the problem however I still can’t get into my wp-admin. I’ve tried wp-admin/themes.php as well and it won’t load. Does anyone have any idea what I’ve done wrong of if this issue is common? Many thanks to anyone in advance that lends a hand.