Hi There,
Welcome to the HealingWell depression forum.
Yes jealousy can make us miserable. All I can say is be happy for those around you. And if it is over a boyfriend or something. Tell yourself that if he is mine, he will be mine. Don't let that greeneyed monster get you down. Put yourself in other peoples shoes. Try to think of what they are thinking at the time. Often that can change your course of thinking. Maybe get a book on it. Reading can help us so much. I know how miserable you can feel when you are jealous. I went through it, found out my boyfriend at the time was trying to make me jealous to lift his own self esteem. So after that it didn't bother me. I hope that you can get over this. Maybe you could tell us a little more about the situation. Whether it is just friends or you SO. Let us know. Either way I know it is a miserable feeling.
Keep posting and know that we are here for you.
Hugs, Karen