Have Headaches, Dizziness And Vomiting. Cause And Cure?

Hi, I have always had headaches all my life. I suffer from seasonal allergies pretty much all year long. But recently over the last few months, my headaches have changed. They are pretty constant and very painful. They usually start with a sharp pain in my left temple and spread throughout my whole head. When I look around, I get very dizzy. They progress throughout the day and get worse. Sometimes they are so painful, I end up vomiting . They wake me up in the middle of the night. I feel like there is this pressure inside my head that just can t escape. I can hear a thud or heartbeat in my head when it is really bad. I ve tried migraine medicine before, any and every kind of allergy meds. But I really don t think they are allergy related. I ve had plenty of allergy headaches before and these are just not the same. What could be going on that I m having headaches this often and this severe?