I have a English/american bull-doggy mix and he is out of control.?

I could walk and/or run with him for hours. We get tons of exercise and have tons of toys love everyone but me and bites me all the time. He is to aggressive. I reinforce that I'm in charge and only give treats for good behavior I love him and he hates me. Is there anything I can give my baby boy to relax? he is only 14 weeks old. Would clonazepam be ok to give him or maybe something natural? HELP!!!