Sandy3,
I never took O2. It's never been prescribed but aerobic exercise on a regular basis helps. My O2 monitor says I'm at 100%.

I so understand the pain of those clusters. I am not chronic tho. You give me strength, dear lady! I have had 4 children and remain committed in saying...I'd rather give birth.
Have you tried drinking a redbull at the first sign of an attack? I can't stand the taste, so I drink a coffee monster. 4 out of 5 times it will help me. I realize not the same thing works for everyone.
Last round, I slept in a recliner. Hubby thought I lost my mind, but it took the edge off...again...for me.
I wish you pain free days from the beast. I really do.

Does 02 help you at all?

Red Bull and other caffeinated beverages trigger migraines for me. I take caffeine pills along with Tizanidine and it's great! It really helps my clusters.
Benedryl tablets helps me with pollen and other allergens. It even helps rescue me from a migraine when other things don't seem to be working.

I cannot stand Red Bull and do not drink coffee. I am a tea sipper. My meds the Neurologist and my Primary give me and my oxygen help me tremendously. I just grin and bear the bad days and carry on. It also throws off my Circadian clock, thank goodness I am retired and I can afford to stay up all night when I get an attack at 3:37 a.m. like clock work. LOL😁