You're 18 now, or will be soon. You're an adult, and you need to remind your mother of that. You should stand up to her, and tell her you're leaving to go to uni. If you want to leave, that's your decision to make, not hers. You're old enough to decide which religion (if any) to follow, and it's unfair for her to force her beliefs on you.
It may be slightly harder for you financially if she doesn't contribute, but you should be able to manage. Your loan will cover all your fees, and your loans/any grants you receive will help towards your living costs, although you may have to get a part-time job.
This is supposed to be the best time of your life, and you're supposed to learn how to live independently. This won't happen if you stay at home. Your mother is being really unfair, and you should let her know how you feel.