You're an adult, so there's no "emancipation" to be done. If you have income, and you file a tax return, and claim yourself as an exemption, then your parents can't claim you as well. The big problem here is that as long as you are FINANCIALLY dependent on them, (i.e., you can't yet afford to move out) they can make any conditions they want (such as being able to claim you as a dependent) on their financial help to you.
At age 18 you are an adult and there is no need for "emancipation". There is however a need for you to formally separate yourself from your family in somewhat different ways. First, you need to meet with a school financial aid counselor to get a clear understanding of how your current living arrangements are impacting your eligibility for financial assistance. You also need to discuss with your parents your financial aid issues. While this may sound harsh, you most likely need to address the issue of being a "dependent" by moving out on your own.
This is not a substitute for a consultation with a family law or tax attorney about your status as a dependent once you are over the age of 18 or no longer a high school student.
I agree with counsel. There is no emancipation because you are already an adult. The dependency deduction issue is one that has to be resolved with your parents.
Please note that this answer does not constitute legal advice, and should not be relied on, as each situation is fact specific, and it is not possible to evaluate a legal problem without a comprehensive consultation and review of all the facts and court pleadings filed in the case. This answer does not create an attorney-client relationship.