What could be causing these terrible headaches?

They started yesterday and haven gotten worse and worse, not responding to pain relievers. It feels as if my eyes are being pulled into my head, and it's a throbbing pain, in my temples as well. I also get dizzy upon changing position, bending over, etc., and the headache worsens too. My vision is a little blurry and it seems to take longer to focus from short distance to a longer distance. My sister and her kids just got over sinus infections, could that be it? I'm not having any congestion though. I know my blood pressure is fine, I checked that already. I also already have gles so I know that's not the problem. Any ideas? Thanks!