Hi there. This could be a migraine , cluster headache, impending rupture of aneurysm will not usually manifest till the aneurysm ruptures. Uncontrolled hypertension is also responsible foe headaches but these would be generalized. Meet a neurologist for an immediate neurological examination clinically and MRI brain, and then the diagnosis of exclusion would be applied. rule out a brain tumor also on MRI. Do not lose time lest an aneurysm is missed. Take care.
no it more sounds like a migraine but you could go get a CT scan done to make sure