I am sure you are not alone, many Buddhists have a different pasts and some have had troubled pasts.
I too used to drink, the last time I drunk alcohol was back around the beginning of this year, possibly around January till March or April, I had a small relapse in November, it was only a little but since then I've never touched a drop and promised myself to stay pure, but trust me, my background is probably far more worse than any of the other Buddhists who have had troubled pasts, I used to be selfish, vain, greedy, bad tempered, rebellious and did things that I still live everyday to regret, but it's never and I mean NEVER
too late to make a change, you still have a chance to be the good soul you are.
Over the time I've been learning Buddhism, I have learned to love myself as well as others, I have learned to be more aware of my surroundings, more compassionate & warm hearted, more forgiveness & not self-centered.
This Christmas I gave a card & present to the Police & Ambulance service as well as my family & friends to show appreciation.
It's true when they say it only takes random acts of kindness to better yourself.