Brief Answer:
Less likely to be meningitis or brain tumour

Detailed Answer:
Hi, and Welcome to :Ask A Doctor service". I have read your question and here is my advice.
Your concern is very right . Headache may be some times serious like menengitis or brain tumour .Howver your headache is less likely to be serious .It more looks like sinusitis for which you have already been advised proper antibiotics.
Headache of menengitis is very severe , and is associated with photophobia and vomiting. .It is very serious condition and if left untreated it progresses very quickly to coma and death in few days .The fact that this headache has been for 2 weeks make meningitis very unlikely .

similarly headache of brain tumours is slowly progressive for months to years and most of the times headache is in the morning .They more likely to cause seizures or weakness. Though still it is a possibilty but very less likely .And we can wait for the antibiotics to work.

Your headache looks like sinusitis. Sinuses in front of the face if infected can produce fullness and headache .This headache is worse on bending and many times follow a flue or blocked nose.

Vision probelms can also cause headache so if you hAve any problem in your vision .

So to be honest , we cannot be sure .But by history your headache looks less likely to be any serious cause.The best way ahead would be that if you are otherwise fine ( No ALARM symptoms as described ahead ) we should wait for the antibiotics to work while using paracetamol for the headache for few days .
If there is any alarm symtoms like , headache that's is very severe , weakness of hand or foot ,double vision , severe vomiting, eye weakness , or disorientation, seizures or any other serious symtoms that make you very sick, or if the headache presists then you should urgently go to ER.

Hope I have answered your question. Please feel free to ask anything else you need to know about this . kind Regards Dr Mahboob ur Rahman.

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