It effected my grades as well. My advice, as the previous people have said, keep a good balance between schoolwork and pot. and NEVER smoke when you should working on something. Often times on reading assignments, I got stoned and read for hours. But other than that, just be conscience of how much your smoking and if there is any schoolwork you should be doing instead of smoking. I hate to turn you away from smoking, weed is really a great thing. Just be responsible with it.