Hello and thank you for your question.
The symptoms from sinus polyp can be headaches or forehead and cheek pain, constant runny nose and post nasal drip, dizziness and disorientation. Regarding the pressure around the back of your head is likely due to the inflammation from the sinus due to poor drainage.
So the symptoms you are experiencing is related to sinus polyp. You need to see an ENT doctor who can provide an appropriate treatment.
Nasal or oral steroids can reduce inflammation and may shrink nasal polyps. Oral or nasal antihistamines can decrease symptoms of allergies. Sinus infections should be treated aggressively with antibiotics. For fungal sinusitis, an antifungal medication may be effective.
Please get back to me if you have any further questions. Thank you.