Thank you for your question.
First of all i would like to tell you that your headache appear to be migraine.
It can be surely told if you describe the nature of the headache quite briefly.
are usually unilateral,severe in nature,throbbing in character,duration usually few hours may persist whole day,periodicity 1-2 times per week,associated with photophobia
,lacrimation,nausea,Aura sometimes present.never associated with convulsion
,fever,altered sensorium.aggravate by sunlight,tea,heavy work and relieved by taking rest in a quite room and sleep.
Please check this characteristics if it matches to you then you have migraine.
But you told you are known diabetic and hypertensive elderly woman having no history of sinus or cold but huge nose bleed today so your nosebleed can be due to hypertension
or sinusitis.Sinusitis sometimes become asymptomatic and nose bleed may be first sign and if you have sinusitis then your headache are due to this sinusitis .
Whatever it may be first you have to do a CT SCAN of the brain and CT SCAN of nose and para nasal sinus then consult a ENT surgeon first and if he will tell it is sinusitis then treat for that and your headache will be automatically reduced but if he will tell your nose bleed due to hypertension or something else then take his advise for treatment of nose bleed and consult a neurologist
for headache and he will help you
please do care of your hypertension and diabetes by regular check up,taking proper drug advised by doctors and life style modification.
Dr Sourav Ganguly