What should I do about my friend?

My friend and I have had a lot of problems lately and now she sometimes gets snappy with me or gets a little attitude when i asks her questions and even when I don't ask her questions. For example today I asked her who she took to homecoming and she said with an attitude for me not to worry about it and that it was non of my business. I don't feel like I can talk to her about anything or even how I feel anymore. I want to tell her how about how she makes me feel but she will probably say that I'm just being silly about it or something and blow it off. So what should I do? Sometimes she can treat me nicely but I want her to treat me like that all the time. She even treats her friends better than me, she is always laughing and joking around with them but with me it's like she is just careless with our friendship.