Yup. I definitely have gotten the I-can't-breath hyperventilating panic attacks. It's triggered mainly by full-body mirrors (like at the gym that I frequent) and showers. I've gotten better at stopping them before they go full-blown (and are therefore publicly noticeable), mostly by taking deep rhythmic breaths and pushing whatever the hell it was that was bothering me out of my mind--which is hard to do. If I can't push it out of my mind, repeating in my head 'I can't change it right now, so stop it' can help. It's sort of like building up a mental callous...
I'm not bothered by panic attacks when I'm in bed or sleeping, but what I does happen sometimes is that I'll get in that really relaxed just-before-you-fall-asleep state, and then start twitching/convulsing. Usually only a couple times, but a few nights ago it lasted for 15-20 minutes and I couldn't stop it; kind of frightening, actually. I really should've just gone out for a run to get rid of the excess energy. I think this is brought on by stress from the day (in retrospect the day when that happened was particularly stressful). I'm sure pushing down whatever bugs me during the day doesn't help either; I'm usually a pretty chill person, but lately I've been noticing that I've been unreasonably stressed out. It's just that I don't realize it until I try to relax... I'm so outta touch with emotions sometimes it's ridiculous >.<