I have asked many questions and questioned my faith often. It would not be healthy to do otherwise. I have seen proof but it is not the proof that you are probably looking for. I have seen the proof in my changed life, and the changed life of my wife. I have seen the proof in the lives of many of my friends who lived in chains of drugs, alchohol, sex, lying, etc, and now have been set free. I have seen the proof in the lives of people I have met in Africa who have left the faith of their families that inprisoned them to fear of spirits, but now they have no fear because they know that their God overcomes these spirits. I have seen the proof in lives of people who have left behind the riches they had here in the U.S. to go and serve the desperately poor in 3rd world nations.
We can not expect to see the proof of spiritual matters in physical things or with our physical eyes.
I've not questioned my faith, and I have no need for proof of God. I seek to understand why people think and believe the way they do.