Once, a chossid came to the third Lubavitcher Rebbe, Rabbi Menachem Mendel of Lubavitch, and bemoaned the fact that he had doubts in his faith of G-d and the Torah.
The Rebbe asked him: “Why do questions in faith bother you?”
The chossid emotionally responded: “What is the question?! I am a Jew.”
Opon hearing this, the Rebbe responded: “The fact that you are bothered by your lack of faith, proves that in your heart of hearts you indeed believe.”
(Igros Kodesh, Vol. 17, Pg. 325)