How do I feel like I belong when I feel like I don't

I know this will sound whiney but I have a friend group of around 8 people then a few other friends who hangout with the group who I wouldn’t see as active members of the group. 
Despite me being a main component, I’m in the “other group chat,” and I get invited to all the functions/hangouts etc, I still feel like I’m not as actively involved as everyone else.
It seems like everyone is so much closer with each other and has their little group/friend and.. I don't 
I feel like I’ve felt this way for the majority of my life. For the first time ever, I’ve had people who wanted me but.. I still feel like it isn’t enough. It’s like people do know me but they dont know me. THey know everyone else though and I dont know what to do or what Im doing wrong to be like this. 
Part of me feels like I'm perpetually always just gonna be like this. Maybe it isn’t the friends who are the problem, it's me.