headache for weeks that comes on when I stand up or sit down for too long

I get really bad headaches with nausea and dizzyness when I stand up for a while or sit down for a while.  It gets worse when I spit out toothpaste, sneeze, and occasionally when I use the restroom (#2).  I went to the urgent care facility. They gave me antibiotics and a painkiller and told me it was a sinus headache.  It has been over a week on the meds and I am getting worse not better.  The color drains from my head and I get really dark circles around my eyes.  What is wrong with me?

[Ms_RoRo]

How long have you been having your symptoms, has it been a week, or were you having the headaches for awhile?

[Dr Sharma]

Hi there. You need to consult a neurologist for evaluation of these symptoms. these could be one of the chronic severe headaches like migraine, cluster or tension headaches. Observe if you have any associated aura of symptoms like nausea, vomiting, dizziness, photophobia etc. postural record of blood pressure to rule out any autonomic instability needs to be kept. trial of medications for preventing migraines like topamax and to treat them like triptans needs to be allowed. MRI brain is required to rule out tumors or aneurysm. Stress reduction and adequate sleep are important. Take care.