Is this a constant pain with no pain free time at all?
This has been reported by others as well
Were you using the proper non rebreather mask and flow rate up around 25lps?
Has happened to just about everyone on this site, We are all here to help you out at any time of day or night! Great place to vent.
A good test that works for most of us is drink a beer- get a attack. When in cycle for episodic and any time for chronic. Some are lucky and can drink with no effect but it is still a good test.
I does not matter if you get one a month or 5 a day, it all sucks and everyone has the right to talk about it. Spill your guts here and we will help clean up the mess