OP I'm not necessarily going to have any practical advice for you but I just want to say that it is possible to turn it around. I was where you are 3 years ago, my circumstances were slightly different in that it wasn't alcohol I was addicted to but I did feel that my life was a total fuck up, that I'd wasted most of my adult life and that my existence was totally and utterly pointless.
The reason I don't have much in the way of advice is because I pretty much had my life changed for me by circumstance, I literally had no choice but to sort myself out or I would have lost everything. Your situation is harder because you need to find your route out of this whereas mine was laid out for me but I honestly think it can be done, you can do it.
I went from the same hopeless, joyless, sad slog through each day to a 'normal' life, yes it has ups and downs like anyone else but it's a million times better than it was. I'm clean, I'm relatively healthy and I'm generally happy, I have the life I saw everyone else living but never thought I could have.
So yes, you can turn it around, others will no doubt have better advice about how you get there than me but I just wanted you to know it isn't too late. I'm a similar age to you and have a lot of regrets about how much time I wasted but I (hopefully) have a lot of time in front of me too and I don't intend to waste anymore. Things get better incredibly quickly once you beat your addiction so the sooner you take the first step towards doing that the sooner that feeling of everything being pointless will stop. Everything gets easier then, hope creeps back in and life feels worth living again.
One piece of advice I do have is to stop focusing on your failures, yes you've made mistakes, we all have but you need all your energy to fight your addiction right now, look forward not back. My past is still ugly when I allow myself to think about it but I'm in a place now where I know it's what I do with my future that matters, I can control that, make it different, the past is done.
Go to your GP, find your nearest AA meeting, find the path that will work for you and stop looking backwards because all that will do is drag you down. What's in front of you can be completely different to what's gone before 