Hi miaxo,
I had panic atttacks too, also precipitated by my XNH. They started when I had decided to leave him and was working up the strength and courage to tell him that I was leaving. And yes, they are awful and I thought I was dying. At their worst, mine would also last for more than an hour, so, you are not alone in this.
I went to the doctor and was prescribed Paxil. At even a low dose, it worked very well and it enabled me to get through the telling, the packing and the leaving with no panic attacks at all !! After I was settled away from him, I gradually went off the Paxil because it does blunt your emotions, all of them not just the anxiety, and I wanted to feel more like myself again.
The withdrawal from the Paxil was difficult for me. It is not an addiction, like you crave the drug, but the withdrawal symptoms were not pleasant. Not everyone gets the withdrawal symptoms though. Even though the withdrawal was awful, I don't regret taking the Paxil, because I NEVER would have been able to actually leave him without it.
Since leaving, I have corresponded with him only by email, which gives me a little anxiety, but no panic. Several moths ago, I HAD to have a phone conversation with him and the thought of it was getting me very close to panic, so my mother gave me a Xanax. (not enough time for a Dr. visit) And that enabled me to get through the phone call successfully.
I have since gone back to the doctor and requested a prescription for anxiety/panic because I know I will have to see him sometime in the near future to finalize the separation of all of our financial togetherness (yuck!!) The Dr. prescribed Klonopin at a very low dose. She said to try it first so I would know how it reacts in my body. So, I did try it on a day when I had some anxiety (not XNH related though) and it seemed to work just fine. Made me a little sleepy though too. Dr. didn't want to give me Xanax as it is addictive.
I am telling you all of this because I am not sure which parts may be helpful to you. But I do strongly urge you to go to the doctor and ask for something, because as I remember it, the panic tends to feed on itself and induce more panic. Because you get so anxious about having a panic attack, you then are panicking about him and the panic itself. So, go to the Dr. soon in order to interrupt the cycle.
I have also found deep-breathing, like you would learn in a yoga class is extremely helpful. When I was without any medication, I found that if I could recognize my anxiety at an early stage, I could prevent an attack with the breathing exercises. The key for me was recognizing the anxiety early on. Once I was in attack mode, it was too late for the breathing.
So, please go see your doctor and discuss all of the issues with him/her and I'm sure that they will give you something that will help. This is a difficult time for you and I know that it is painful and disorienting. And I also send you peaceful, blissful thoughts as well....
Gingerpeach