Don't you still have a nagging doubt about the big bang and inflationary universe scenario?

I have doubts, to be honest. The theory is based on the current state of the Universe expanding at an accelerating rate, which is true. But by deduction, the Big Bang theory plays back the process of expansion, and arrives at the only conclusion that a "playback" of expansion can arrive at: that all mass and energy must therefor have started from a point of singularity. We are basing this theory on a very short period of observations and postulating a theory to define a Universe that is over 13 billion years old. We don't have more than theoretical constructs for the nebulous ideas of Dark Energy and Dark Matter. The Universe is a vast, immensely old and complicated thing. It seems like a large step to accept the Big Bang at this point based on our actual scientific knowledge. In addition, accepting the concept of an infinitely small point of space containing all of the Universe's mass and energy, and then "exploding" for some unknown reason takes a leap of faith, just as the concept that an omnipotent deity created the Universe. Faith is a poor substitute for sound conclusions made by the scientific method. Big Bang theory may be correct, but I do have my doubts.