Self esteem issues are nothing new to teens, especially girls. I myself have delt with self esteem issues, and the best way to start feeling better is to figure out what might be causing you to feel that way. It could be the music you listen to, the people you hang out with, anything that bring you down. If a person is saying rude and hurtful things to you, you should stop talking to them and report them. Remember, NO ONE HAS THE RIGHT TO MAKE YOU FEEL BAD ABOUT YOURSELF.
Another way to feel better about yourself is to learn to love yourself. When I would see that quote I would always ignore it, however it is important! Maybe don't like your hair, but you love your eye color! If you can identify things you like about yourself, you're on your way to a high self esteem! You could make a list of things you like about yourself and save it for a bad day.
You can also help get rid of your self esteem issues by getting involved with a team sport or club. It can help to talk to friends, because more than likely, they've had similar issues!
As for your paranoia issues, you should talk to your parents to see about getting a therapist. If you google symptoms, you may end up misdiagnosing yourself, which can be very bad! You could end up believing you have one thing and allow what you actually have to go untreated. You may want to tell your parents the severity of your anxiety. If/when you tell them, make sure to think out what you will say and how you will say it. Explain why you may feel this way and ways they can help. It is important to suggest ways they can help because it may stress them out to have a problem and no solution. If your parents will not listen, you should talk to a guidance counselor, sibling or friend.
Hope this helped!
GymnastPower (Girl's Advice Column)