Rule #1: If you can't control it, don't let it control you.
Being angry at somebody else for being happy, or rich, or whatever isn't going to change your situation or theirs.
You're young. Set goals. You're the only one you have to impress. There's no finish line, or trophy stand. So what do you want to accomplish some day? Set goals to get yourself there.
The only person you can truly depend on is yourself. So decide where you want to be, and start making the choices that will get you there. Life will sidetrack you, and it will help you reevaluate if your original plan was really what you wanted.
Regrets and revenge are just going to waste your time. So see rule#1 above, and do your thing.
On edit: I think that's the most sappy positive thing I've ever written. How wild is that? My nickname used to be the Prince of Darkness and not because I dressed in black.
Sounds right to me, and wise.
I try not to rent any extra space in my head to a really bad day once I get home, just celebrate the fact that time keeps moving even when I'm not having fun. I like to let each day have its time and then stay in its place in the past, so the next day I can feel as a fresh start.
"Sufficient unto the day is the evil thereof." (Matthew, 6:34)
As far as comparing myself to other people is concerned: I learned a long time ago that I'd only be comparing my insides to someone else's outsides. I have no idea what goes on in the head and heart of someone who's cheating, lying, stealing. I cannot live like that and that's really all I need to remember. Maybe the other person is a sociopath. I'm not, so I need to hang onto my integrity and my sense of right and wrong.
An injustice is sometimes a thing that cannot be remedied, and when that turns out to be the case, I can only try to let go of it. Otherwise it will consume me, and what good is that (especially since I'm the one perpetuating the thing by constantly recalling it). I have once or twice written a sketch of an injustice, everything I felt about it, and folded it up and burned it in the woodstove to help me put it into the past. I don't want to be looking over my shoulder in envy or resentment. Today's the only day I can do anything with. Yesterday's gone and tomorrow is at best a plan, not a reality. So I try to make today a good one, even if it's just something simple at day-end like listening to music I like or making dinner for a friend.
Best of luck to the original poster.
but we make our own luck, really.