HELP i am addicted to masturbation.

Your advise is needed.

I am so addicted to masturbation that i dont fancy guys
I don't insert my fingers or anything in there, I just rub my cli*toris. The thing is that I don't even need to watch p*rn or see anything to make me ho*rny, I just become ho*rny for no reason or mast*rbate to kill boredom.
Lately, I've noticed that I become very h*rny when I see girls with big b*obs. Anytime I'm about to take my bath, my own body turns me on and I mast*rbate. I don't even last for up to two minutes anymore because I'm so used to it.
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I've prayed, fasted, cried to God and talked to pastors about it but I still can't get my self to stop it. I also feel so guilty about it when I'm through and ask God for forgiveness but I think God doesn't even listen to me cos I always go back to it.
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I dunno if it will affect me when I'm married. I need help please. I need help on how to stop it and please no one should advice me to think of something else when the urge comes cos it will come back stronger the next time it comes.
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Please help me, I know it's a sin and I don't want it to lead me on a smooth ride to hell.