It sounds like your mom is going to need some kind of counselling once she's released from the hospital. People who are in their right mind do not go ballistic and smack their adult children around and take handfuls of aspirin in a suicide attempt when those same adult children start making adult decisions about their lives.
This is classic control and manipulation behaviour that domestic abusers employ. Has she always been this way when you didn't do what she wanted?
Personally, I think you should get out while she's in the hospital and never look back. Maybe even talk to the police about filing an assault charge on her. If you've got any bruises or scratches from her beating up on you, get a friend to take pictures, or go to the ER and get them to do it. They can be used as evidence to support your charges. Make sure the cops know that she kicked your ass for not wanting to be a JW anymore. If you really want to make her life miserable, you could take your charges to the elders and get her reproved for physical violence, and say that her behaviour toward you makes "living in the world" very attractive compared to "staying In The Truth?". Then tell the elders that you reported the abuse to the police and that you told them that the beating was because you told her you didn't want to be a JW anymore. They really hate it when someone Brings Reproach on Jehovah?.
Her behaviour is inexcusable. Don't coddle her and let her get away with it. You can love someone without allowing them to abuse you.
Love, Scully