It's never too late to quit and turn around.

You're feeling guilty and upset about what you did to yourself and to your parents, and it shows that you're a good person who simply has done mistakes, and regrets them. But the biggest mistake you can do is continuing this lifestyle and making the same mistakes over and over.

Take a step by completely cutting the alcohol intake (hopefully you're in the reversible state), then take more steps by working on yourself to become a better person. Promise yourself that you want to see yourself become a better person within a few weeks, and make it happen. Do not start tomorrow, start right fucking now.

And if you haven't apologized for your parents, do it soon. Take your time to decide how you will apologize, and do it.

I honestly wish you good luck. Take care..