hey richie bro,
i'm guessing that there must be stacks of decent advice in those 10pages of posts which i haven't had a chance to read but this is what i wanted to tell you from personal experience...
when i was 17/18y/o & made it clear i wanted out of the "troof" i had no idea what opions were available to me, and so went back...clearly there's no chance of that with you since you have loads more backbone than i did when i was your age...but since then i've lived in a bunch of different cities, in different countries even, and i'm well aware of all the options open to me, and different support I can obtain from local organisation etc in this situation. I'm sure that in a few years time you will see your situation now even more clearly than you already see it now. You will see that there are more options open to you than just sticking it out at home during this rough trot and working your job at Target. You may think in time, why the hell did I put up with all of that crap? So my advice is to think that the sky is the limit, and to use your gutts and instinct to rapidly improve your current situation.
I agree with Little Toe that your mum is just being a typical JW nazi, mine was too when I first left. But having said that there's no reason why you should wait till the 11th hour to move out of home if you're getting this much grief already matey. It's not healthy for her or for you. I know it sucks to be turfed out of home so young, but you're strong and you will manage and cope your way through it. This is as hard as it gets for you in life, never again will you ever have to go through such turmoil and hardship.
In hindsight if I had of known all of the options open to me I would have realised that I would have been eligible for a pension on the basis of the situation going on in my family home. I would also have called on non-witness friends allot more than I did to help me through the hard times. I would have seen counsellors and psychologists through the national medicare scheme free of charge, and I would have used local ngo's who offer bond assistance to move out of home earlier, as well as sourcing flatmates through the local paper etc.
Good luck bro, and keep us posted on your progress. If you decide just to stick it out I fully understand, you just do what's best for you, as no-one else will :)
luv you matey, sis frog xox