Hey, gorgeous.
Whoever made you believe that you aren't good enough was wrong. You are more than enough.
You are strong and beautiful, a work in progress. You matter. Every little thing you do matters. You have fire in your soul and you need to let it burn. You are brave. You are worthy of love.
I can tell you what you're not. You're not required to tear yourself apart to keep other people together. You are not in any way required to fit in. You are not a finished product. You're not obligated to stay in toxic relationships or apologize for being yourself. You're not responsible for fighting a battle that's not yours and getting caught in the crossfire. You're not a disappointment. You're not alone. You're not invisible.
Never again let someone else determine your worth. Don't let someone tell you that you aren't good enough, or that you can't do something. Work on yourself. Make yourself proud, don't be worried about what anyone else thinks. This life is yours, baby, do what's right for you. Stay away from people who hurt you; don't leave and go back. Get rid of whatever negativity is dragging you down. Give yourself reasons to be happy. You're alive, you're breathing, and I can promise you that someone loves you.
Love yourself and stay strong.