You are not a lost cause, and there is hope. The first thing you have to recognize, and I think you have, is that you are not like your mates. For you, alcohol is both a poison, but it is also an allergen in the most severe sense of the word. You most likely have a genetic predisposition to alcohol substance use disorder combined with early usage has got you to this point, and there is no going back to moderate use. You really must stop drinking altogether.
What you have described is alcoholism and it is nothing to be ashamed of. It is a disease. It is no different than cancer or any other type of affliction, though people will try to tell you otherwise and shame you for it. Willpower is not a part of the equation for you once you move from problematic drinking to alcohol use disorder.
All you can do is get professional help and recognize that your goal is to eliminate it from your life. When you cross over to this state you cannot solve this problem on your own. I would very much encourage you to seek some sort of in-patient treatment center that lasts for at least 45 days if not longer. Perhaps your parents' insurance can help with this. This is critical. If you try to do this on your own without the education, without the medical monitoring, without the skills they teach you to cope and get to the root of the problems that cause you to drink, you will not find success.
It will not be easy to eliminate it from your life and given how much you are drinking you will likely have to go through a controlled detox period to not endanger your health. And then they will teach you the skills to manage the addiction and avoid substituting with other addictions. Relapse tends to be a part of the process, but the key is to try to minimize and avoid it as much as possible.
The good news is that you are young and have already come to the realization that alcohol is extremely damaging. Some people take years before they come to that realization and only usually after permanent damage to themselves or others has happened, or an accident or some sort of resulting criminality has forced that to occur.
Right now, to you, it feels like you have reached rock bottom, and hopefully this is your rock bottom . . . feeling left out in relationships and feeling that you have disappointed others (parents, etc.) . . . and this is a good thing. You want this to be the worst consequence of your drinking that causes you change, but do understand that you are so, so lucky if this holds true, as many people permanently damage their health (i.e., cirrhosis, kidney and heart disease, brain damage, etc.) or have an accident that hurts/harms themselves or others before they come to this point of realizing they must stop.
Speaking from experience, the first several years are the worst, but as you adapt to life without alcohol, and built the skills you need to socialize without it, it gets much easier. Ten years in, I don't even think about it, and go to parties and socialize like everyone else. The difference between me and my mates is that while they are drinking a martini, I'm drinking a club soda with lime.
In fact, I find now that my conversation is wittier and more engaging as my brain is fully recovered and sharper than it ever was before. And, I can modulate my emotions so much better. Most people that have substance use disorder got there because they were self-medicating for some other issue like anxiety (even moderate social anxiety), depression, etc. The key is to not only treat the alcoholism, but also the associated disorder that you were self-medicating, and going to some in-patient type treatment will help you get to the root of it.
Make sure to do your research on a facility that offers the most services and gets the best reviews, and talk to your parents about this.
Alcohol is a poison that damages every organ of your body, including your skin, but most damage is done to the liver, kidneys, brain, heart and vascular system. Depending on the level of your addiction the damage that your body will need to repair could take a year or up to five, but your body can do that, with the exception that once you have cirrhosis it is irreversible and you will succumb to that disease within 1-12 years depending on how far it has progressed. Jaundice sometimes is one of the last symptoms with people so don't assume because you do not have jaundice that you won't get it, but the odds that you have it now are slim because you are young and your body is resilient.
When your friends experience you sober and over time regain trust and respect you will repair those friendships. Your parents love you immensely and they will always feel that way. They are just concerned, but again, time will ease their concerns when you demonstrate that you can control this.
Likewise, when you learn to manage the issues that you were trying to medicate with alcohol, when your health recovers, and you learn "healthy" substitutions such as exercise, engaging in hobbies, journaling, etc., you become a more interesting person who is actively engaging in life . . . getting things done, adding value to his life, and people notice this.
Best of luck. You can do it.