I think that you probably just need some higher quality stuff, I know that I've smoked garbage and hardly felt a think but then other times - wow.
As a side note I think that smoking mj occasionally is fine but, don't make it a habit. They say you can't get addicted to it but I know from experience that this is not the case. I'm fine now but for awhile I as doing it everyday. I didn't get the shakes or anything when I didn't but, just felt off until I did.