Code red,
If you're a guy, then I know you probably don't want to open up and tell her how you feel. IF you're a girl, you can try that, but either way it's still a good idea. You can also try to not keep promises you promise to her, so she'll figure out how it feels. My sister doesn't do this, but she does things similar to it. This stuff works for me because my sister is sensitive, hence it may not work for everybody, but it's just a suggestion based on personal experience.