I can relate to your post in so many ways.
Be very careful with the thinking that you'll only use cocaine when you are drunk. I thought the same thing and then I quit alcohol months ago but I kept using. So make sure you focus on quitting both and take both addictions very seriously.
Also, 6-months is great. You obviously can live the sober life you just have to sustain it. Learn from your mistakes. You thought wine would be okay, that's what got you to drink again but now you know it isn't. Don't ever forget that.
Try to figure out why you are getting the urge... What is it you like about alcohol? For me the only thing that worked was learning to hate it and learning that the benefits I thought I was getting from alcohol weren't in reality a benefit at all. In a sense I was drinking for no reason at all.
Don't let the alcohol/drugs trick you. We've all had good times using but don't let that become what gets you to use. Always remember the bad events you've had while drinking and using when you get the urge... Replay the events over again and again and ask yourself if using is worth the risk of the potential of events happening again and make no mistake it WILL happen again if you keep using.
Another point - One of the main reasons I was able to quit was like you I knew I was getting taken advantage of due to alcohol/drug use. It's not a good feeling getting taken advantage of. I knew sober these things would never happen so that helped get me to hate alcohol/drugs. If you hate something there is no temptation... No temptation = no urge.
I'd also keep coming to this site, even if it is just to read. There's a lot of good people here who will be willing to help you and you can learn from others mistakes and success stories.
I see a lot of myself in you. I want you to know that if I can quit so can you!