Oh boy, I can relate to this so much, but the good thing : it can change, but with time. God as change me in one year in ways I coudn't even imagine. And I am so curious to see where He will lead me next.

First thing, however, as frustrating at it may be, never fake interest, this can only lead to a path of hypocrisy, apathy and more frustration with yourself.

Don't smile, dont fake interest when you don't have to. It will make you miss some connections at first, but it is a necessary step. Of course, don't be a jerk putting that unnecessary sad face either. But make an effort to be kind to other,s without pretending to be someone that you are not.

Now let me tell you my experience, of the biggest change that occured to me, that made me go from an introvert, to a little less introvert.

Once you grow with Christ, and you realise more our weaknesses, our sins, our nothingness that won't make the face of the earth any better, you will start to see the beauty of having earthly interests and passions. You will see beauty about people that care. You will see beauty in people that know that clothes are not the holy grail, but they care about presenting themselves in a Godly way. You will see beauty in the guy that workout, even though he seems a little dumb but he seems to put is heart into it. You will see the beauty in the women that try to finish all her job/study obligations by saturday beacuse the weather is nice ans she wants some tan. And when you will start to genuinly see the beauty and the effort that it requires to care about those things, you will slowly become more curious. Not because you will suddenly be interested by those things, but because you will care a little more about the person and his reasons to do whatever he does.

I think that caring about simple things is a humble thing. Sure, people might idolize their body, clothes and their sun tan. But most people are simply trying to do their best on this earth, in whatever way they can, and when you realise that everyone knows the same struggles, and that everyone is in the same boat, you will slowly feel that desire to relate and to connect more with those people, your peers, the only people that you can only relate to, even though they might be on another point of their growing journey.

Hopefully it might help a little. I am still on that same journey as well. I have a small social circle, but I am able to have a better time with people. I naturally smile more often. People are also less afraid to talk to me, because I seem more open. So it's definitely not easy, but they are definitely good results. And trust me, caring about wordly stuff havent not furthered me away from God either. It's rather the opposite, because I started back on good fundations.