I'm a bit sick of sad puppies like this. If you want her, go find her and tell her and pursue her with all of your will and strength. If she's hanging around with a bad crowd or doing bad things, tell her once clearly that you feel she's not going in the right direction, but don't push it. She's her own person; not a doll for you to control and attempt to own. She has the choice to make bad choices.

You can't keep hanging onto the idea of her if there's no chance of being with her. Stop acting pathetic and either go get her or move on.

Protip: No girl wants a sad, weak little boy who can't voice what he feels and is too scared to act.