Can my parents legally do anything to restrict me when I am 18 years old?

My parents took away a phone that I purchased with my own money, they took away a car that I am currently paying off, they told me I cannot see my 18 year old boyfriend. They have said that I am not allowed to talk to any family members for help. They have restricted my way of getting to work and I cannot work now and must quit my job due to lack of transportation. My mother told me that if I wanted to leave there was nothing stopping me and then she did not let me leave without telling her where I was going or who I would be with and when I would say to see my boyfriend she would say I am not allowed to see him and when I would say my friends she would not allow me to go. She has said that I cannot participate in academic trips or any of my senior activities although I would be paying for them all. I paid for a prom weekend house and she said I cannot go. She confiscated my debit card so I cannot access my money. I am using all my own money for everything I do and I am 18 years old.