First time smoking

Okay so today my boyfriend asked me if i wanted to smoke he didn't force me or anything but i said okay so were both smoking a blut & all of a sudden i feel my body getting light headed i was in & out of daze i couldn't breathe i told him to call my mom & she took me to the hospital & i told them what happen & when they checked my heart date it was like 156 which was bad for my age so they put me on a heart monitor & then it went down & they put me on fluids. I just got home right now i just don't know why i couldn't breathe i couldn't talk i couldn't stop shaking i was dizzy i was seeing things & he was okay he was crying because he didn't know what to do & i was trying to calm us both down does anyone know why this happen?