I hope this will give you some consolation. I'm a very extroverted person, everyone in my sphere of study and family think I'm a very well adjusted young man, always taking interest in people and share my own experiences. I don't visibly mistreat themself and I'm on top of my studies, doing loads of extracurricular stuff.
I'm telling you this because if you met me, as a shy person I imagine I might fit the profile of the sort of out going person you'd want some of the qualities of, but behind closed doors I'm actually unbearably lonely as well.
The journey to self confidence and acceptance will probably get harder before it gets easier, but I believe you can do it. I think that once you begin to reflect on what progress you have made, however insignificant that is, you'll become content with where you are right now and less disorientated searching for that next milestone.
There's so many people out there also wishing people would just initiate the conversation first, looking for thoughtful people who aren't going to be a chore to be around. Please be kind to yourself, I believe the world will surprise you if you don't withdraw from it yet.