My friend is using me.. What should I do?

Hey guys, I was wondering if you guys could give me some advice. I've been friends with this girl for 3 years now. We've spent lots of time talking with each other, and hanging out on the weekends. It has always been friendship based, not romantic. Recently, however, i've realized that she never takes an interest in my life. Our conversations usually consist of me asking ehr a bunch of questions, and her answering them in as few words as possible. I have been helping her with her work since I met her, almost doing it for her, expecting that when I finished, we would talk and hang out. However, I've noticed that it has turned into me doing her work so that she can go hang out with other friends, who are my friends as well. A couple of days ago she gave me her phone to play with, and I saw a texting conversation about me open when i got it. It was between her and one of my other friends, mike. It said that she needed to call me to get her essay edited, but right after that she would leave me and talk to him. I'm sick of putting in this effort if I don't get anything out of it. She means the world to me, but at this point she's hurting me more than she's helping me. Should I confront her about it? should I leave it be and continue what i'm doing? Should i just stop talking to her? I feel like i care so much about her, it would be almost impossible to continue on without her as my "friend", but how she treats me makes me feel like I don't matter. Any advice would be greatly appreciated. Thanks!