I'm trying to access my website using
mysite.com/wp-admin but whenever I type in my info and login the page does not load and won't open just a white page shows.
Sounds like a theme or a plugin is causing the problem. Try renaming the wp-content/plugins folder to quickly disable all plugins and then try logging in. Add the plugins back into the wp-content/plugins folder to find the culprit.
If you have access to the error log file (assuming the site is not that busy), then you might find the error message pointing to the 'bad' file (plugin or theme).
Try this tutorial on the 'white screen of death': http://www.wpbeginner.com/wp-tutorials/how-to-fix-the-wordpress-white-screen-of-death/ . (Good site for learning.) Their instructions include temporarily disabling plugins, and then trying a different theme (by renaming the theme you are using in wp-content/themes ). Usually the theme or plugin.
Most likely you made a change to your theme and made an error. Which does not allow to parse the code correctly resulting in an empty page.
Depending on your server settings it will show some errors or just a blank page for safety reasons.
I suggest you rollback your last changes, one by one untill it works again to identify what change created this behavior.
Open your 'wp-config.php' file at the root of your install. Set the
WP_DEBUG option (near the bottom) to
true and save.
Reload your site, and any errors should be printed above your header - hopefully that'll point you in the right direction if it is a theme/plugin issue.