white screen of death upon upgrade to 2.7.3 - site + cp

I recently upgraded my EE install from 2.2 to 2.7.3 and now I can’t access my site or control panel. Turned on debugging, error message:

Fatal error: Call to a member function userdata() on a non-object in ….EE_Typography.php online 1158.

Line 1158 is as follows:

if ($this->smiley_array === FALSE OR $this->parse_smileys === FALSE OR ee()->session->userdata('parse_smileys') == 'n')

Any ideas?? Help would be much appreciated. Thank you!