Why does weed have such an extreme negative effect on me?

Drugs like that affect people in different ways, but what you're describing is fairly common from what I've witnessed. Memory issues and emotional outbursts are among the top problems, but they won't just affect you while you're taking the drugs. The effects seem to be long-term from what I've seen. If they bother your senses, judgement, and the ability to lead your life normally, then I suggest you quit. I personally had to quit for much of the same. I suffer a brain disorder which severely effected how the drug worked on my body, and needless to say it was never enjoyable to me. So ask yourself, to the positive outcome you feel you get outweigh the sometimes debilitating negative reactions you have?