can't log in to dashboard

I’m pretty sure I corrupted the footer .php file in my blog when I added the tracking code for google analytics. I was getting this error message at the top of all of my blog pages when opening-

Warning: Cannot modify header information – headers already sent by (output started at /home/content/v/a/n/vanderloo/html/blog/wp-content/plugins/polldaddy/polldaddy-xml.php:1523) in /home/content/v/a/n/vanderloo/html/blog/wp-includes/pluggable.php on line 881
But otherwise the pages are fine. Problem is, now I can’t log into my dashboard. I’m getting a blank page with this same error message. Is there a back method for getting into my dashboard or does anyone have another solution. I was able to get there fine last night. Nothing has changed since.
My second guess would be a corrupt polldaddy plugin since this is mentioned so many times in the error message but, again, I can’t get into the dashboard to disable it.This did occur after I updated all of my plugins.