I really could do with some advice..?

three months ago i moved out of my mums house, she and i never really got on, at her house i had two little half brothers and a step father. Since my seccond half brother was born i was pushed out, it then became the 'william and marcus' show, (not litteraly speaking) So for a while we argued, It then got to a point i couldnt handle it, I am a thirteen year old girl, and although i am wise beond my years i feel i am handleing heartache that is way to mature for me, i am now in a situtation where i am living with my father, his wife and three other half brothers, i go to see my mum ever twoo weeks for a couple of daysbut everytime i leave i feel washed over with hurt. Now im not sure what to do, My father is overjoyed to have me, and my mum is hurting because im gone, but if i move back in it will hurt my father. I havent slept propperly for a while now and im verry high strung. I just need some advive please