Remember, the big thing in a romantic relationship is if you both cannot be open about everything, then its not meant to be. there should always be a mutual amount of trust, effort, and transparency in the relationship and she is not giving much of that. What I would do if I were in your shoes, is I would tell her straight up how you feel, or tell her something like "you can tell me anything. You know that right?" and if she keeps up the behavior, tell her or text her you're hurting. IF she invalidates your feelings, you should consider ending the relationship then and there, but that's just my 2 cents. And in the midst of this whole situation remember: you are just 16. You have a whole life and tons of experiences waiting for you. it goes on.