I used to have this problem too. I have a sibling who is still struggling with it. My rock bottom, so to speak, wasn't pretty. Tore my family apart, put a rift in a lot of good friendships too. I still carry the guilt, but I've mended ties with the family and we've all moved on.
But there's great news! You've identified the behavior and want to change it. Without that self-awareness and desire to change, there is nothing but rinse and repeat.
As I'm sure you're figuring out, the guilt will fucking eat you alive without mercy. The flipside of that coin is the incredible relief, accomplishment, and empowerment of coming clean and giving honesty the reverence it deserves. Paraphrasing my father, what value does a relationship have if it's based on untruths? It's no longer a true relationship at all if it's based on fiction, rather it's an obligatory act of "going through the motions," doing the bare minimum to maintain some level of a connection. Any relationship worth its while will be able to weather the truth, and if it isn't, then the result is at least genuine.
It sounds like the people you care about, and the people who care about you, already know that you're untruthful. I know my family did. What a horrible burden, for everyone, to deal with that elephant in the room. Come clean. Apologize. Openly acknowledge your struggle. But you better damn well be 100% committed. Offer your vulnerability as a down payment on the future, it's the only credibility you have left. The freedom of guilt is truly intoxicating.
From then on, it's all about personal accountability. If you're doing something you won't want to be honest about, then stop doing it. Regardless of what you do, own up to your actions and their consequences by being truthful about it. It's a positive feedback lop, promoting the values I think you recognize as worth having. Your current situation of lying, feeling guilty, the resulting poor choices from your self hatred, then more lies... Well, it doesn't go anywhere pretty.
God I wish I could hug my dad and thank him for saving my life...
Don't take your family for granted. They'll be the last ones waiting to pick up the pieces if you let them.
Well, this is more my story than yours, but I hope you can relate. If you find a moment of courage, I hope you just blurt it all out and free yourself of your burden. The consequences are scary, but at least they're real. If you can find the resources, I'd definitely recommend talking to a professional. They're nice, and it's their job to be easy to talk to. They'll have you asking yourself all the right questions, and hopefully help you find peace.
Cheers,