People who reject and abandon themselves often feel jealous. People who love and value themselves do not feel jealous. They are not threatened by others, because they know their own intrinsic worth.
The more you learn to love and value your unique essence, the less you will find yourself comparing yourself to others. There is only one you. You are incomparable!
Fear of rejection is a big issue for many people -- and it used to be for me, too. I used to be so worried about how others felt about me that I was often anxious in my interactions with them -- always trying to say and do the "right" thing so they would like me or at least think well of me.