'debs, I'm willing to bet that we have had at least 50 people here who have said that oxygen didn't work for them. In at least 90% of those cases, having the right oxygen setup and using it right changed everything. I would really strongly suggest that you read the file I linked you to before -- this one: https://clusterbusters.org/oxygen-information/-- to be sure you had the right setup and were using it right. You can dramatically change your relationship to CH when O2 works for you.
I suggested some other things to you in my post above -- D3, energy shots . . . -- and I'd strongly urge you to try them. If you're at the start of a potentially long cycle like your last one, the D3 can help you a lot.
I'm hoping the steroid taper will help. A week is a pretty short time for a CH taper. 10 days to three weeks is more common. If that doesn't resolve your CH, verapamil is the most commonly prescribed preventive.