To dream of a pitbull represents emotional protection that is projecting a sense of danger for any misgivings. A strong show of assertiveness to keep others in line. Making boundaries and the consequences of violating those boundaries very clear. A constant sense that "if you f*ck with me I will kick your ass." Making it understood that jealousy will never be tolerated and embarrassment will occur if someone doesn't listen to you. Confidence that doesn't scare at all.
Negatively, a pitbull may reflect tendencies to be overprotective. It my also represent your feelings about someone who you feel is more powerful than they are intelligent. Alternatively, it may reflect your own arrogance that keeps others feeling threatened to keep them in line.
Example: A woman dreamed of a pitbull trying to help her defend herself from an attacker while she personally felt unable to scream or speak. In waking life she was a grandmother that was having arguments with her daughter-in-law over getting to spend time with the grandchildren. She tried to get aggressive in the arguments chastising the daughter-in-law for not respecting family enough, but it didn't work.