LBF, you just moved in and probably have not even paid the 2nd month rent yet. You got to slow things down and think. You knew what you were moving back into when you decided to move back in with the grandparents. Did you know the situation about the rent you pay and the rent you aunt pays? If you did and didn't say anything... that is your lost. It seems like you rush into things without thinking... no logic behind what you do... you just do it. I think you really need to slow things down and see how everything goes the next few months before you even think about moving. I really can not see you on your own... you are not ready for life. The situation you are in might be bad but is it unbearable for you right now? Chill for few months, get your GED in that time and see how it goes before you even think about or decide to move out AGAIN.
If you do decide and move out again... good luck. Because if I had family member that kept doing what you are doing by moving in and out like that. Do not even think about coming back when you have no where to go. I think it will be the 3rd time you moved in and out the past year all within 1-2 months of moving in.
YOU ARE SHOWING YOUR GRANDPARENTS NO RESPECT BY DOING THIS when they let you move back in for the 3rd time.