Website traffic dropped to 0 after theme install.

Hello,

I have a small website where I write some gaming guides and resources for various titles. It has seen some steady growth from search and I was averaging 400 - 450 users a day. It suddenly started to take a dip and I noticed my site speed was causing some issues with my search rankings.

Last night, I was searching for optimized themes and apparently 'the fastest' and switch to a premium theme called 'Newspaper'. I logged into my analytics today and noticed there hasn't been a single user to the website.

All of my URLs have stayed the same so I'm not positive what might be causing this. Anyone have an idea?