The situation with your Mom sounds very difficult. However, it also seemed as though your Dad and Grandma were more supportive. I would talk to them about how you feel (stating your feelings calmly and clearly will probably have better results than whining). Making on line friends is a good way to feel less lonely, but also it would be good to make friends in real life... playing basketball would indeed be a good way to do this. See if your Dad would be able to intervene for you, just on this one thing.
We're here for you, friend.