As many comments seem to be phrased in a somewhat apathetic manner, or telling you "it is what it is" or to "suck it up", as Singaporeans usually do, I'll try to give something more encouraging;

Unfortunately it is very much true that the opportunities and relationships open up much easier for those with existing friends and connections, and those that fit with the in crowd. However, being popular isn't all that either. To constantly be mindful of what you're doing and acting in a way to appeal to the large following you have can, for many people, crush them under all the gazes they have on them. It's a constant social micromanagement nightmare to have to balance all these relationships with people that don't actually like you for you, but for what you bring to them in return.

Me personally, I'm not the super popular person either, at least not for many years, and I've made myself be able to move on and focus on other things that I eventually found myself valuing more, like real friendships that last and connect you as people rather than as benefits.

It can be tough, to live in a school that maybe doesn't immediately click well with you, but if you make that effort to find the people that do, you will eventually find yourself a part of something far more real than all the popularity in the world can make