splitting

halkova An instance where something splitVerb splits.
puhekieltä A division in the mind, or affecting one's sense of self.
2007, Brett Kahr, Sex and the Psyche, Penguin 2008, p. 308:

In other words, something troubling, such as being discovered in the toilets in a shaming way, can be both remembered and also pushed to the periphery of consciousness, a process that psychotherapists refer to as ‘splitting’.

I have a splitting headache.