yesterday i took my bike (for the first time in a year) and went to het some cigarretes. i dont ussually exercise and i went pretty fast and in total (going and coming back) i biked for 20 minutes. when i got home, i drank a sip of water and took like 3 puffs from a marihuana joint (i live in the netherlands so its legal). i started feeling weird and i could feel my heart pounding in every inch of my body, so i stood up to get some air and my vission went black. i knew what was happening, i just couldnt see. i grabbed a stool and started shaking, but not like shivering, it was more as if i was convulsing, with continuing hard shakes. eventually it stopped and i sat on the couch and closed my eyes. after 10 minutes i stood up to go to my bed, and my vission got grainy and then black again. my head felt really warm and i was having cold sweats. the water i had had felt as if i had had a gallon of it and with every step i took i could feel it moving. I went to sleep and woke up ok. Does anyone know what happened?