Please see this: http://www.blogyoutrust.com/if-ever-you-see-your-cat-or-dog-do-this-please-take-them-to-the-vet/
And please also read the other articles provided at the end of the link above.
Head pressing is characterized by the compulsive act of pressing the head against a wall or other object for no apparent reason. This generally indicates damage to the nervous system, which may result from a number of varying causes, including prosencephalon disease (in which the forebrain and thalamusparts of the brain are damaged), or toxic poisoning.
Head pressing in cats: http://www.petmd.com/cat/conditions/neurological/c_ct_headpressing