I was a believer. Got "saved" too. There were always doubt though. Then i thought long and hard about why i believed and realised there was no reason i had besides faith.
And faith is not a good reason because you can hold any position based on faith.
For the most part you are correct. So the muslim, christian, mormon, zoroastrian, hindu, space-monster, fairy/pixie belivers all cant be right can they? Because you will find people in all those and hundreds of other belief systems (which frmly contradict each other) who firmly believe their god-belief or whatever is the true one.
So how do you tell which one is true? You cant because as you said, you cant prove a god doesnt exist...but they cant prove theirs does either!
I take exception to darwin in your listing only because i assume you mean the theory of evolution. For which the evidence is mountains high.