What will Happen if i run away from home?

im 17 years old im a sophmore in high school im very smart it seems as tho i cant do anything or even if i do im always in trouble with my foster mother but the 1 thing i hate is everytime i make a friend n get close to them she always runs them away like 2day i get home at 4:15 she gets mad bcuz im 15 minutes late then she gets a phone from a friend of the family saying that i was sittin on a boy lap which i was not she just went crazy then she went off on my sister what should i do?