I know what you mean about the emotions. I give myself permission to express emotions at a time I feel is appropriate and that seems to satisfy them. Although I probably come across as over emotional at those times. And when under extreme stress and the right amount of hormonal imbalance I can definitely snap, as you mentioned. Lucky for me I'm a woman and most people excuse the behavior. I do find myself in awkward situations where everyone else is expressing emotion but I just stand there trying to fake it. But I kind of like it, it was definitely a big help when I was there for my grandpa when he passed. DH freaked the #$%& out like normal people would, so I think it was better for me to be there than any other family member that wouldn't have been able to handle it.
The only time I've had panic attacks they were caused by my social anxiety. They were mild though and I've always been able to talk myself down. I've never had the full blown, heart attack version.