Hi,
Your symptoms are suggestive of acute sinusitis. It will help us to know if you have any nasal congestion or runny nose.
Headache due to sinusitis usually worsens on bending forwards and is associated with pain behind the eyes.
I would suggest you to do steam inhalation at least 3-4 tmes a day and once before bedtime and take OTC nasal decongestants.
If the headache persists please schedule an appointment with your GP for a clinical evaluation.
Oh that's awful!! How bad is the pain on a scale of 1-10? I really feel for you! If the pain is a 9 or a 10... I would suggest going to the hospital. They can give you medications that can probably stop the headache and maybe even prevent this headache from returning (sometimes stopping the pain cycle will stop the headache).
Also, are you taking OTC drugs for this headache? A lot of OTC drugs such as Advil can actually cause rebound headaches... so if this is a dull lowgrade headache that you are feeling... and not a bad intense headache... then it could be what is called a "rebound headache" since it has lasted for so long. You might want to stop taking the advil... but I would do this under the care of your doctor as the pain might get worse and you need a back up plan with your doctor on what you will do if that happens. It is always good to discuss your pain management plans with your doctor before changing anything drastic... such as completely stopping advil cold turkey or something.
I hope you feel better soon. If you haven't already been to the doctor at all, then I'd really suggest going... especially if you aren't at a hospital point yet. You should get this checked out if you haven't already. You could have a sinus infection that needs antibiotics... or you could have developed a migraine disease... or you might need eye glasses because you are suffering from eye strain...
I hope you are feeling better soon! Headaches are awful! Especially ones that won't go away. I know that it's like. I feel for ya.