My site is down and I can't access the dashboard

The plug-in is hummingbird and this is the error message:

Fatal error: Cannot redeclare wphb_src_to_path() (previously declared in /home/content/p3pnexwpnas04_data02/21/3838921/html/wp-content/plugins/wp-hummingbird/helpers/wp-hummingbird-helpers-core.php:10) in /home/content/p3pnexwpnas04_data02/21/3838921/html/wp-content/plugins/hummingbird-performance/helpers/wp-hummingbird-helpers-core.php on line 10