Ok, try this :
Clear your cache through the options, if that doesnt work, do it manually (it is located in AppData, you might need to google it for more precise steps)
Log out from this site and from facebook, and close your browser to completely close your session. (on phone too if needed)
Try another browser like Kajex suggested and/or reset your browser settings to default (you might lose your shortcut tabs and specific configurations but yeah...)
Normally this should fix it.