I'm shy. Why do people think I'm snobby?

So, I was speaking to one of the members of my group during a project at school. Apparently she thought that I thought I was 'better than everybody else' and 'haughty' I asked her to explain, and she said that it's because I don't talk to people a lot. This stunned me, because I don't even see myself as appearing very confident (because I'm not).

This has also happened before. A few people have thought that I would be rude or look down on them, just because I'm afraid to start conversations! Do they think I'm ignoring them? Ahh

Shy people, has anybody ever thought that you were like this? If so, why??? Also, did you fix it?