back in '06 i quit smoking for a year or so because i started having anxiety attacks. maby panic attacks. never had one and didnt wana tell anyone so i didnt know what it was. i thought i was schizo or goin crazy till my friend described one that he had. never lasted as long as yours though. he called it hot headed. sounds like symptoms your having, the breathing and weird head shit, i never had the intense pain but it coulda been in your head, but the other stuff kinda sounds like it. ive heard that some strains of pot are anxiety inducing but that might be bullshit. seriously thought i had a screw loose scared the shit outa me. i just quit for a while. doesnt happen anymore. trippy shit though. then again maby i am fucking crazy. ha. look that anxiety shit up see if thats maby what it is. good luck.