People often share the same feelings, regardless of the relationship. Sometimes even strangers feel the same way. You might have a friend who is like a sister at heart (more of a sister than your own biological sister, if you have one). Or it could be a crush who feels the same way you do.
If you're asking what to do in a situation, know that other people feel the same way you do. Maybe you could join together for a cause or something like that.