Hey man, I was reading your latest blog and I thought you could use someone to talk to. I went through the exact same thing as you, and I figured I'd share my story.
I was a pretty devout Christian most of my life. I grew up in the Roman Catholic sect of Christianity. I attended an RC church every Sunday and I even went to an RC school for eight years, which I graduated this past June. I'm now a freshman and I'll be starting public school this Wednesday. I don't remember the exact date when I came to the conclusion that I no longer held Roman Catholic beliefs, but I do know that I had been questioning as far back as 2010. I know I've been an atheist for a few months now. You can imagine how free I felt when I finally graduated from Catholic school and no longer had to lie to myself about beliefs I no longer held.
However, family does often pose some problems. I live my my mother and my grandmother, who are both Roman Catholics. My mom is pretty chill about it, actually. She doesn't attend church regularly and uses no logic whatsoever in her beliefs, but she doesn't ride me about not believing in God. I can always talk to her when my grandmother is causing problems for me. My mom has relented to allow me to make my own decisions regarding "Confirmation," which I have elected to not continue with seeing as I don't believe in it anymore.
My grandmother, on the other hand, is convinced that some awful entity on the internet corrupted my mind. It's terrible, really. I wish more than anything that she'd accept me for who I am and accept my beliefs, but she seems to think that I'm purposely doing this to hurt her, which is so far from the truth. I wish I could change her mind, but so far, I've had no luck doing so. The best thing I can do is just be civil when talking to her but always stay firm in my (dis)beliefs.
A friend of mine from ZD, Matt, showed me this video: Uncle Atheist's Advice - YouTube
Caution, the language is quite foul at some points, but I found it pretty helpful. It's very blunt, but I think you can take out good advice from it. Feel free to ask me anything or talk to me if you need to. Just know that there are many people who are going through the same thing you are and you're not alone.