Can't really add much to what's been said already... SOO much good posting.

I know how you feel. As a teenager, it's often nearly impossible to feel God working in my life, and questioning Him and Christianity as a whole sometimes much easier than trying to reconcile myself to faith.

That said, the basic message here is: IT'S OKAY. Not everybody can be 100% sure of God 100% of the time. The important thing is not to let this nullify the good He's done for you, or make you blind to the good He may well do later on, or be doing now. Don't stress, don't push yourself towards something you're not feeling. Just keep your mind and heart open, and don't stop talking to God every now and then. Sometimes it's surprising how much He listens, and what He's saying in return.

Luck and love,
~muse

P.S. Wander around outside on a beautiful sunny day. That sometimes helps me refresh my sense of wonder.