I would suggest you were never a true believer, a true believer never falls away. He remains faithful until the end.
Many Christian's have "walked away from God" during thier lives for one reason or another..thank God He's patient (prodigal son) and waits for us to return back to Him..we don't lose our salvation just because we aren't doing God's will 24/7 in our lives..He doesn't love us any less..so yes..you can STILL be a "true believer" in spite of yourself...