When I first tried coke I had the same experience. One of the things you might want to try for starters is looking for a new job. I know it's not easy to just up and quit, there are obvious consequences and a million excuses why you can't - but working in a bar you will find nothing but trouble. I know because I was also a bartender and at one point was doing coke in the bathroom during my shifts. The 'bar crowd' is always going to be filled with drug addicts, alcoholics, and the overall scene is short-sighted and unhealthy.
I just got sober 8 months ago so I'm no genius, but there's no way in hell I could have done it while working at a bar. Those 3am-4am closing shifts, the need to be "on" and awake late into the nights, sleeping until noon, etc - all of these things are breeding grounds for potential addictions. Again I know it's not what you want to hear, but there are some fundamental changes you need to look into in order to achieve what you're looking for...sobriety. I hope you agree and think about it!
Best to you!