The thing that you are finding so irksome about a trust is the very thing that makes trusts attractive to many people: The person who established the trust need not
make the terms of it public"”and is free to change his or her mind about potential beneficiaries at any time.
Any lawyer who helped your mother set up the trust would also be legally required to remain mum about its terms"”or risk violating the client's trust, which could subject that lawyer to discipline or even disbarment.
By far the most common types of trusts are testamentary. A testamentary trust is one that will go into effect once the trustmaker dies, so there is a good chance you would not be entitled to any trust assets until after your mother's death, anyway.
It sounds as if you've talked with your mother about your desire or need for money now, but she seems unwilling to accommodate your request. Your reality is that you will likely have to look elsewhere for money at this time.