You may not be smoking weed. Weed doesnt make your throat swell up and or even make you trip. You could've possibly smoked spice or k2. From a personal experience I actually thought I was smoking pot once when I was actually smoking spice. Had a similar reaction to yours, I freaked out and kept telling my friends "take me to the hospital, my throat is closing.". It was just a scary experience. The last thing is you could be allergic. Not sure how weed reacts with allergies or much about that though.
my sister is allergic to thc.. ( i think?) because when she EATS it she gets sick for days with diarrhea and vomiting. It's almost ridiculous how bad it gets. Now, as for your problem...who knows. When I first started smoking I could smoke a lot and it was great. But one night I got super paranoid and it was never the same. I never completely stopped but to avoid extreme paranoia, I'd just smoke very little...enough to feel good but I feel totally in control. I'm building tolerance and slowly but surely I can smoke more and more. If it makes you feel like that, try smoking very little. If that still has your trippin balls, maybe you really are allergic and should just stop.