Cohiba, based on your response, it doesn't appear that your circle of friends is the main issue, and I believe you. It sounds like you might be your own worst enemy. I get it. Coke will bring you down eventually, booze will bring you down eventually. You are doing both. You sound like a really smart guy and know what you want to do, its doing it that's the problem. Something has to click in your head, some rational thought, that will assist you in being able to say "no" to yourself or that line on the mirror.
I don't like to talk about this as it was long ago, but I used to do coke when with my buddies, I loved it. I really did. These guys were mid level distributors so it was free and it was pure. We'd do these 2 day binges, strippers, the whole 9 yards. At that age it was cool, right? Wrong, while we were doing this, there were kids our age getting their engineering and medical degrees while we played scarface. Eventually I wanted out, I wanted to grow up. I didn't want to be 40 living that lifestyle. I'd seen those guys and I knew what I thought of them. So, I had an a-ha moment. I did it one last time about 4 months later, didn't like it. Haven't touched it since. I had opportunities in my 30's to participate in that behavior from time to time and just said "sorry guys, don't do that anymore, you guys knock yourself out". Same with alcohol during the week, I'm a contractor and am offered alcohol all the time after work with other contractors. I politely decline, and they'll usually offer me a water which I always take.
You can do this Cohiba, I know you are feeling low right now. This weekend try very hard to walk away from it. You won't hate yourself come Monday. But you know that.