I'm glad you are ranting, that way I can simply say, waaaaaaaaaa! stop your whining.
you are doing a lot of comparing yourself to everyone else and you obviously are delusional in this regard, because not everyone's parents buy them cars, not everyone is doing much better than you, etc. While we are on the not everyone's parents bandwagon, not everyone has parents that will lend them money, will let them live with them until you get on your feet, etc. Seems to me, you have it much better than many people I know whose parents aren't so caring or helpful.
the good thing is that you realize that you've made dumb mistakes. The good thing is that you are young enough where the impact is minimal. The good thing is that if you look at your hands and feet you have 10 fingers and 10 toes and two good eyes to see them all. You have no idea the situation of everyone your age. there is quite many people in debt your age and giving appearances of being better off. there are quite many people who you might think are doing better, have a better job, etc, who are equally as miserable as you. the thing to realize is that your life belongs to no one else but you, so stop trying to live it as such.
for every person who seems to be luckily, there are 10 thousand more who have to make their own luck. you might just be one of among us that have to make our own luck. so be it, life ain't fare if you constantly compare yourself. i find a common theme here.
anyways, there is my rant to your rant. you are fine. you are young. you are healthy. you have family that care about you. you realize your mistakes. you are correcting them. it may take time, it may take a lifetime. find a niche that makes you happy and focus on that, and everything else follows.
there are lots of things you can do with friends that don't cost money.