a similar experience happened to me when i moved and had to quit for a couple months cause i couldnt find shit. i think its more mental than physical. when u feel like u cant breathe u start to freak and overanalyze things in your head. also its important to be in comfortable surroundings whenever you do anykind of drug. plus your brain is changing alot at your age from when u started at 14 to now, u might not feel the same now when u smoke as u did then. also try to say goodbye to cigs i know its hard and a habit but if you have good green fuck cigs. also exercise more to keep your lungs healthy. a sedintary lifestyle will fuck your body up quicker than u think. thats why so many americans are obese cause they dont have any physical outlet. your not the only one whose felt like that so dont worry u just have to make some changes. good luck