Parents...invasion of privacy??? i need some opinions?

i am 18 years old, a senior in high school and have recently done a few i guess you could say "rebellious" things that have my parents wondering whether or not i should be trusted. Today however, i found that they have basically set my intercom so that from the comfort of their room, they can enjoy listening to every conversation i have/ move i make. ALSO, today my mother decided to go through my car, and my room, where she found an empty beer car, and a wonderful pregnancy test, leaving her AND my father believing that i am irresponsible, and not to mention , a , which i most certainly am not. so i would just like to know, is this an invasion of my privacy? or are they entitled to spy on me and rummage through my things just because they are my parents??