You're wrong. You are worth the air you breathe, the sun on your face, the clothes on your back, the food on your plate, and so much more.
Atelephobia is the technical term for the fear of not being good enough. It is extremely common, especially for college aged students and those who suffer from mental illness. As someone who has struggled with atelephobia a good portion of my life, I understand how hard it is to convince yourself that you are good enough. But I am also here to tell you that you are good enough.
Look into the mirror, and smile. While sometimes it may be hard to believe, you deserve that beautiful smile. Thinking you're not good enough often leads to thinking that you do not deserve the good things in life. A lot of times people will take the little things, such as a sunny, cloudless day, for granted, but for others the little things are what will place the first smile of the day on their face. If you are struggling with atelephobia, focus on the little things that give you joy and realize that you deserve them. Realizing you are good enough for the small things will eventually help you to realize that you are in fact good enough for the big things and everything.
If anyone ever tries to tell you that you are not good enough, look them straight in the eyes, and tell them they are wrong. No one, besides you, has the power to determine your worth. Take this power and use it. Create a mantra and tell yourself you are good enough and you deserve happiness. Even if you don't believe it at first, saying something enough will eventually convince yourself of its truth.
You are important to someone, probably a lot of someone's. If you were not good enough for others, you wouldn't have friends and your family wouldn't bother with you. But you do have friends and your family cares for you. Surround yourself with only people who make you feel as though you are worth their attention and your happiness. Do not let others make you feel less than or worthless. If a person makes you feel this way they are not worth your time and should not be a part of your life.
Happiness is something that everyone deserves. You are worth happiness and all the other big and small things that cause joy to you. It won't happen instantaneously, but eventually you will be able to convince yourself of the truth, that you ARE worth it.