You’ve already given up a lot. The sheer act of realizing that this habit repels others and interferes with your hopes for something better in your future, like living awhile longer, means you’ve given up an attitude. Perhaps you’ve already let loose other self-destructive parts of your lifestyle. Perhaps you’ve lost someone dear to you already. 
When you let go of a support, no matter how shaky unhealthy and unstable it might be, it’s likely you’ll stumble and come crashing down unless you have replaced that support with something else to grab, to hold you up when your foundation shakes. The key is to find and choose something sturdier, healthier, to replace the former thing you used to run to.