~~"I can't judge and blaspheme God simply because I don't understand God; I do not have that right."~~
Your argument of not knowing enough about the universe to challenge God on anything is very valid, but I can just as easily turn it around on you and say "We know so little about the universe, we amount to so little in the cosmic scheme of things, so how can you claim to know the nature of God?" I see the argument of ignorance to be an argument for pure agnosticism, if anything. If you're going to say "We're all in the dark", the statement applies just as much to the believer as it does to the doubter.
~~"Why did he choose this day, at this church, where I never go to, to address this subject?~~
Well, my sarcastic side wants me to say "Your preacher was possessed by the Father of Lies to manipulate you down the wrong path", but that would be just mean. :-D
It is, at the very least, a remarkable coincidence. Although, for every person that gets an encounter like that when they need it, many others go without. I've been in your situation many times before where I doubted and agonized over questions like this, in the time when I still considered myself Christian and was fighting to find a reason to stay so, and I had no miraculous source of answers like that... I'm sure you've had similar experiences where the only answers came from yourself. I can't offer any concrete answers, to be sure, but just be careful not to "Count the hits and forget the misses" to quote Sagan. If every really fortunate thing in your life is attributed to God (like recieving answers from unlikely places or opening a book to just the right page) and attribute all unfortunate things to blind chance, there's a weird kind of double standard going on there. Not saying you're doing that, but I've noticed it in a lot of people before. I honestly don't know. I can tell you what I think happened based on my worldview, but that's just an opinion.
At the very least, was the answer you recieved as good as you hoped? Let's here it. :)