How do I win her back..?

We've been together for about a year now. And she tells me after work one day that she needs to talk to me. She said she doesn't feel the same about me anymore. Just the day before she's telling me how much she loves me and all this amazing stuff. I've never cheated on her, never done anything she doesn't like... I don't know what I did..? She doesn't give me a reason or anything. Just drops me like I'm nothing. I'm feel so broken and empty. I've never felt this way before... It's literally hurts worse than anything I've ever felt before. She said maybe we'll be together in the future, just not right now. She expects me to just let her put me to the side until she feels like getting back with me. I don't know what to do. Should I keep trying.. Or just give up? Do you think I should wait like she wants? Please help?