Don't worry, you're not alone. There are things that can't be explained. But think about this everytime you get nervous. Have you been harmed by anything? If you haven't, you more than likely won't be. If you have or if you seriously feel threatened, you have to tell you parents/guardian/adults. If they don't believe you, I'm sorry, it's rather common that they don't, but you still need to. All I can say is have faith, if not in God, then in good.
My 'door' was opened a long time ago, when I was much younger than you. I was fortunate to have a good mother, who may not have believed something was happening, but she still believed I believed. And she comforted me.
If you like you can email me. I'm very willing to help you. I don't like the idea of anyone feeling like that.