Ignore the PPs who suggest that your friends with seemingly perfect lives have secret struggles or tragedy. They might, but that's not the point. Schadenfreude is not the solution to your problem. On the one hand, you could still get lucky. Or you could make a list of actionable items that would lead to your vision of success and then, you know, take action.
I've had my own struggles with comparison and jealousy, for sure. I work hard to make my life what i want it to be. When you do that, it's amazing how little someone else's good fortune affects you other than to just be genuinely happy for them. Someone will always be richer, younger, more beautiful, better educated, better traveled...
There was another recent thread similar to this one, some good advice there too:
http://www.dcurbanmom.com/jforum/posts/list/670534.page