Since you were God's idea; you are a good idea. Yes, you! The one that was created in His image to do good works. The one that He knew in your Mother's womb. So when you feel all alone or are in the attitude of not liking yourself Remember God likes you and He has prayed for you. So there is no reason to stay in that state of mentality.
I know it is alot easier said than done, because I struggle with low self-esteem. I struggle with being a pessimist by nature. But that is not who God wants me to be. He has made me to be more than a conqueror. Not just to conquer something or get by, but more than a conqueror that is a pretty amazing thought. The Bible also states to Be strong and of a good courage, so we can have that confidence in yourself through the Lord Jesus.
So know that you don't have to stay defeated or down, nor do you have to stay negative. God has created you for a specific purpose. You are special and you choose to allow Satan to keep you defeated and listen to his lies or know the truth and truth shall set you free.
