Website and log in issues after 3.8.7 forced update

My problem is two fold.

I cannot log in anymore because the page insists I enable cookies. They are enabled and I have already tried clearing my browser caches in both safari and chrome. I am still not able to log in.

Also, various pages on my website are now displaying a variety of this message instead of my content: Warning: Cannot modify header information – headers already sent by (output started at /home/content/g/l/i/gliver06nowKSW/html/wp-content/plugins/akismet/widget.php:1) in /home/content/g/l/i/gliver06nowKSW/html/wp-includes/pluggable.php on line 896

On this page ( http://metalartsguildsf.org/event/), clicking on event listings brings up the header warning. What I am noticing is that the word “wordpress” is being inserted into urls where it shouldn’t be. http://metalartsguildsf.org/wordpress/mag-events/
Removing the “wordpress” part brings up the proper page….