Severe pressure headache?

lately ive been getting a pressure sensation in my head, not my ears or eyes, or forhead, just at the top of my head, and i cant even dive 1 foot undewater without the need to come back up because its intense the pressure i feel not even a foot underwater. i had bronchitis last week and the doc gave me antibiotics because he said i also had a sinus infection but i didnt have these symptoms then, and my bronchitis symptoms went away. what cud it be? and the headaches are daily now.