no psychosis is NOT a stretch in actuality , perhaps you should do your research before discounting the possibility , it IS possible and it DOES happen.Those that experience it have a genetic predisposition that makes them MUCH more likely to experience it, particularly after long term MJ use.
perhaps some reading at these links may help
http://www.webmd.com/mental-health/news/20110301/marijuana-use-linked-to-risk-of-psychotic-symptoms
http://en.wikipedia.org/wiki/Long-term_effects_of_cannabis
I do not believe this to be the case of the OP but do not dismiss a notion just because u do not know about it.
but , as I asked first did user ever suffer panic attack, and he has answered that he indeed has but just does not/ did not know the label of what was happening to him. weed can and does contribute to anxiety and panic. I have dealt with panic attacks, I know how they work and how fucking down right life threateningly scary they are when they are happening to you.
I will suggest u lay off weed all together until you get you panic issues in check. The brain is a very powerful beast, supremely complicated. This may sound or seem stupid but u have to reassure yourself that what you imagine is happening to your body is "all in your head" and not in your body. I have found a shower to be one of the best ways to head off panic attack. You get these thoughts of bad stuff in your head and can't seem to get rid of them. whatever it takes to get your brain to "think" of something else besides what you are panic-e about.
I hope in some way this helps you, these attacks are in your head but the "suggestions" such panic brings on are very real to you. the KEY thing you said , was "couldn't breathe" THAT is classic panic attack. I suggest you keep a small brown paper bag handy as most likely when u said u can't breathe you are hyper ventilating. wrap one hand around top half of bag, stick a finger into the top opening as if you were going to try to blow it up to pop the bag, place the opening of the bag to your lips and inhale and exhale with the bag kept to your lips.
pcpvapors feel fee to contact me via pm if you would like to discuss panic issues.
again, I hope to have helped in some way.