I have a similar issue. My error message:
Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 122880 bytes) in /data/3/0/18/145/181308/user/[xxxxxx]/htdocs/wp-admin/includes/menu.php on line 126
I tried to activate Jetpack comments and now I don’t have access to my dashboard at all.
Thanks for any insight!
Anne