We pretend to be strong because we are weak. - Paulo Coelho

You are what you believe yourself to be. Don't be like those people who believe in "positive thinking" and tell themselves that they're loved and strong and capable. You don't need to do that because you know it already. And when you doubt it — which happens, I think, quite often at this stage of evolution — do as I suggested. Instead of trying to prove that you're better than you think, just laugh. Laugh at your worries and insecurities. View your anxieties with humor. It will be difficult at first, but you'll gradually get used to it. Now go back and meet all those people who think you know everything. Convince yourself that they're right, because we all know everything, it's merely a question of believing. Believe.

And if I’m alone in bed, I will go over to window, look up at the sky and feel certain that loneliness is a lie, because the Universe is there to keep me company.

You are what you believe yourself to be.