Amy123,
From my read of what you wrote, you are much more knowledgeable about CH than your doc. Great news, yet not so great. I'd throw it out there that you might want to find another doc that has experience with CH, but better would be to see a neurologist that's knowledgeable with CH. O2 script should be the first line of attack on the beast.
You might get lucky, but most people on pred, our CH beast comes back toward the end of the pred taper.
A few things of note: Check your diet. Remove anything that is high in Tyramine (aged meats, any natural cheeses, any fruits or vegetables not immediately fresh. Have you tried energy drinks for the attacks? Slam an energy drink at the first twinge of an attack (then get on the high flow O2). That should significantly help with the pain level and duration of attacks. Make sure when you get your O2 that you stay on it for approx 10 minutes after the attack stops. That'll usually help delay your next attack. My attacks restart very quickly if I don't stay on the O2 longer than just the attack.
I'm sure some others will chime in here shortly with more and better info.
J