It’s easy for someone like me to be glib in response to your anguish. I’ll try not to do that with telling you that you should love yourself, that you’re the most important person to believe in yourself. No. Those things may be true, but how to get there is the universal rub.
I would suggest that you get hold—easily available on Amazon Books—of Mark Williams & Danny Penman’s book; Mindfulness: An 8-week plan for Finding Peace in a Frantic World. It’s a Rodale publication.
I suggest this as this is a quite easy to learn form of meditation that research has shown done some wonders with all kinds of human frailties and dilemmas such as yours. It’s a great way to see not only what you think, but also how what you think an fantasize about affects how you perceive yourself. Give it a shot. I’ve recommended this to many of my patients and all report very good results about the things with which they struggle.
I’m assuming—I hope not wrongfully— that you are a young person. I’m likely quite a bit older and more experienced which leads me to the following which you’ve no doubt heard before causing your eyes to roll back in your head; but stay with me with an open mind: These things, they ways we find ourselves so wanting and defective as a young person change as you get progressively older. You get to the point that you not only accept yourself, you may even find pride in who and what you are. Believe me, it comes, and I must say, quicker than you know. I know, my friends I have gone through it. Seems to be part of the evolutionary human condition.