1 semi-complex word, 1 simple word: placebo effect.
This is NOT meant as a bash post or to belittle you or your beliefs. I was raised a fundamentalist. I never totally bought into it after I learned Santa and the tooth fairy weren't real. But I did try. I figured the adults were smarter than I, and if they believed it to be true, then it probably is. But after growing and learning on my own, and actually reading the bible, I came to the realization that there probably isn't. Why? Because a god is not necessary. It is an answer for the cosmological answer, but it doesn't make it true.
My life has actually improved since coming out as an atheist. I am not praying for my life to be fixed every night. I am actually DOING something to better myself. I prayed for too many things that didn't come true. Everything that did, I was doing something to help it (like, praying for wins during football season. I bust my ass in practice and, what do ya know, I play well and my team wins).
There is no evidence for the existence of god. Again, I am not bashing you for your beliefs, please don't take it that way. I am simply offering a worldview option just as you are.
You were praying for the wrong things, and most true Christians don't pray for those things. They do exactly what you do - live their lives the best they can.