Vibrating dildo

I have never been one who orgasms from the g-spot, always only the clit. With that being said, sex has been difficult for me throughout my life. I can only orgasm when I'm on top, and it has t been with every, or even a quarter of my partners. I recently purchased a vibrating dildo in hopes of expereincing a g-spot orgasm. I tried it for the first time last night, and nothing. What am I doing wrong? I had it on full power (I eventually orgasmed with it on the clit), I tried in and it, I tried leaving it in, I tried all the way in, I tried partially in... Nothing. Any advice?