Trouble Breathing due to bad trips?

I picked up smoking about 3 years back. I was in 11th then. Thereon, my smoking increased. By the end of grade 12 i was quite a smoker. Id smoke a pack a day (mostly). About this time i tried weed, the first time i felt nothing but the second time there was a high. Then i took a break for about 2 months. A cigarette occasionally ensued. I entered college, and continued smoking. Here again i was smoking quite a lot. This time however, i went to my friends place for weed. The experience was very bad. I started suffocating and cannot forget the feeling. The next day i was fine. Cigarette smoking continued, however i made attempts at stopping it, convinced that it was life threatening. About when my first year was gonna end i quit smoking finally. However during the holidays my friend introduced me to a bong/pot smoking. I tried it, however the feeling came back. It was not so intense but still similar. It troubled me the entire night. In the morning i was better. For about a week or so i was smoke free. Then my friends birthday came and we all drank some alcohol. My friend offered me a normal cigarette drag (im sure it did not have any kind of weed). I declined but on further insistence i took two drags. The feeling came back. This time the problem did not fade away. Ive been having attacks in which i feel there is some blockage in my respiratory passage. Its been about two weeks and it doesnt go. Ive been to doctors who say that i have mucous stuck in my passage. I feel there is actually some inflammation in the passage. Can somebody tell me what wrong with me?