How long have you been taking the Cymbalta and are you taking 60 mg or more? I have fibro too, and have been lucky that on Cymbalta I rarely have flares anymore, and if I do, they aren't very bad.
I know what you mean about anxiety and panic making the pain level go up, up, up. I had that problem in the past, and it's very frightening. I had lorazepam for a while for anxiety. It sounds like a benzo is not an option for you now.
I don't have any great advice for you. I would concentrate on pain control. If you are still having significant pain while on the Cymbalta, describe it to your doctor. I ended up being diagnosed with a type of autoimmune arthritis that affects soft tissue in addition to the fibromyalgia. For a long time, all the pain was being attributed to fibromyalgia.
I take Arthritis Tylenol now for break-through pain (not that strong, I know, but more helpful than people expect.) It's 2 650-mg time-released tablets.
Another over-the-counter thing I use for pain that helps me because it makes me sleepy and relaxes me is called
Salonpas. It's a patch containing menthol and methyl salicylate. I like it because you can put it right on the spots that are hurting worst. It was recommended to me by a pain specialist as "something extra" to use.
I found regular massages and acupuncture treatment (if you find someone who knows how to treat fibromyalgia - I went to an acupuncture school) to be helpful with fibromyalgia pain, too.
Sorry I don't have more ideas about the anxiety. I don't think my anxiety was ever as severe as what you are talking about. It usually wouldn't turn into panic.
I hope you find something to help.