Please don't take this the wrong way but are they genuinely being nasty or are you not happy because you can't have what you want? I only ask that because the majority of the time my 18yr old son feels the same way about me as you do about your parents because he can't have what he wants. An example being "why can't I have my idiotic, destructive friends round for a house party?" Sometimes parents can see where you are heading with a course of action you may be taking and want to stop you making the same mistakes that they undoubtedly did when they were your age. Sorry if that comes across as patronising but I couldn't think of any other way of wording it .
When I was a young whipper-snapper I rebelled against my parents a bit, but looking back I was just being a right ungrateful little monster. They really do just have your best interests at heart