while you have already received very good guidance from Milfoil and Laurel_belle, might I just suggest to you that wolves are not predominantly violent creatures... they are frequently very shy, and remain within the structured protection of pack and forest. They are very strong animal spirit companions to have, and I cannot believe that your wolf would be evil and cruel.
Wolf as companion suggests pack law and pack wisdom; family, and protecting the family; ability to track down what is needed to nurture the self; ability to survive in harsh conditions.
The fact that yours is raging in your dreams suggests to me that you may be repressing the nurturing, family tendencies in yourself, and that you need to let the "pack" aspect of self come to the forefront...perhaps spending quality time with your family members and a few beloved friends will help correct the balance.
As a teen, one can often feel split from the family and the parental unit, so maybe the division is hurting or scaring you. Perhaps your friends and natural tendencies are creating this rift; time to heal it a little, without becoming dependent again, like a little child. Try visualising your parents and family as friends, not relatives...I know it helped me a lot to do so, as a teen.
Good luck, and don't let thoughts of evil sway you. As Milfoil suggested, some time quietly spent meditating with your wolf companion may well restore the balance. You will see it is not a violent monster, after all, but a gentle, protective creature who wishes you nothing but the best