I feel like my friend is controlling. Help!! What should i do?

I have been friends with this girl since freshman year. Now where going into our junior year. We started out as really good friends with not many problems.. But when i couldnt hangout she got mad said "well i guess your just too busy for me your like all my other friends who are busy" or your 16 you nees to live your life. She also talks about her other friends behind there back and im pretty sure she does it to me. When she first started saying all this stuff to me i did feel like i was the problem. She can be controlling too im going on vacation for 3 week and ive told her a bunch of times and she got mad at me lastnight and trying to get me to cancel my flight and just go for a week and i said no i cant do that! She trys to controll who i hangout with ive lost some of my close friends when i started hangingout with her and i understand thats my gault she always got mad when i was with them. She wants to goto college together too but im goingnto try to get as far away as i can if i go out of state shes not coming with me. Ive tryed telling her about the college thing like going to start fresh and meet new peolple. Her response "yeah together" thats not really the answer i want. At first i felt like i was the problem but now i feel like she is the problem i want my friend to not judge me or critisize me or talk about me behind my back. What should i do i need advive?!