>>101240feeling jealous is never wrong, unless in some specific and complex cases, but even then it isn't necessarily a problem because it's just a feeling (acting on it is another story, and justifiable only in a handful of cases).
don't feel bad about being jealous.
however, with time, it's good to get past it because as the nona before said it simply isn't worth it.
don't waste your time and energy with people that don't deserve it. let them have their life, and build yours with more compatible and valuable friends. it might take a while but it will be much more worth it.
for a start, i'd ditch the group in a subtle and drama free way so i wouldnt have to waste more time on them and suffer from feeling left out.
then i'd start looking for other people that have something in common with me, interact with them and seeing how it goes.
it's important to remember that there isn't anything wrong with you. a lot of our anger and sadness whem rejected comes from insecurity and the ego blow it gives us. but, it's just a question of compatibility (or sometimed of the other person's issue) and not our own worth. detach your worth from being accepted in groups and decide you're worthy no matter what. it will make things much easier.