To ask this question is to
bring your reality tumbling down.
If you question reality, then how can you stand? (logically speaking)
It's like trying to build a skyscraper by dynamiting the foundation. You can't get anywhere, because by questioning reality, you question yourself (you being a part of reality), and by questioning yourself, you bring your logic, and therefore, your original question, into question. So on and so on, ad infinitum, ad nauseum.
You just have to accept it, for now, until you get some evidence that you aren't a part of reality.