My initial thoughts upon reading your post is to give up weed and any other illicit drugs altogether. Then since you mentioned 'nutrition', I would think that perhaps you feel inside that sometimes you are not eating right. So make sure that you are eating healthy from now on.
If you are not already doing so, become physically active too to ensure that you get lots of exercise into your life. With these three main factors, they should being you much improvement to your life.
If and only if your issues still exist, then at least you've taken some major steps in your life to become a healthy person. The next step would be to get professional health for any outstanding issues you may have.
This is the progression I would recommend. Good luck.