I just cant stick to my plan of gaining weight?

15 years old & i'm 5'4 & 95lbs. im usually around 90lbs but gained weight this week from eating. i have an eating disorder.. this is the 5th time ive tried to gain the weight and eat normally but i just cant do it because i look alot fatter than what i weigh expecially my stomach. and as soon as i start gaining a bit of weight my mum starts being a ****** to me, and i just cant get past the image i see in the mirror with the family i live with, as soon as i gain weight my mum allows my brother to hit me because she doesnt have to worry about my bones being brittle. and this is when i start to stop eating again and lose 10 pounds. i dont know what to do. should i commit suicide or what should i do? please help im so unhappy :(