I have no problem accessing the other k2 tabs (cat, tags, etc) but when I click on k2 items I get a fatal error

Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 13704792 bytes) in /home/content/24/6542724/html/libraries/phputf8/mbstring/core.php on line 121

specs
joomla 2.5.14
k2 2.6.7

everything is updated and has been for couple months without this issue, it just started no new plugins added except rokbooster.
I have a very large amount of content within k2.