I’m sorry to hear of your struggles. Given what you have described, it may be that the sequence of events triggered an unconscious memory or fear. Your panic attack may be in reaction to that deeply buried fear (an extreme flight/fight response triggered in the amygdala). These types of fears and panic responses are emotional, not logical. Often our logical mind cannot reasonably grasp or reason with such fears. Even a competent therapist who explores any underlying fears may need more than 6 sessions. That said, it does not sound like this therapist did that. In lieu of therapy, it might be helpful to journal about this and examine your feelings and fears. I wonder if both events triggered uncertainty and the go to response in your unconscious mind was to “create certainty” by having a ready solution that would, in theory, pre-empt loss (by controlling the loss via breakup) ? In other words, by feeling you can control loss you alievate the panic response to your deeper fear? I have no idea if this is correct but you likely do. Another possibility is that getting married can create anxiety for even the happiest couples. Combine all three and it may have been enough to create an unconscious fear reaction and defense. You seem quite clear you love your fiancé and see you together in life. So if you see no reason and had no significantly negative experiences with him, dig deeper in your feelings to uncover your fears. Logic will not solve your panic feeling, but facing your fears and working through them can. If you and your fiancé are open to it perhaps you can do this together. It is often amazing the insight you can gain from those closest to you. We are greater than our fears. I wish you much peace and healing so you can emerge your confident and joyful self.