Realise that you don't have to be the loud or funny one to still be apart of something..
For instance my friend is nice, placid, pleasant, yet I wouldn't consider her to be a loud or a show off sort of person, yet she is still relevant and a friend...
So once you realise that there is a side to you that can be fun, maybe it depends on the group dynamics as to how you react around others, and that is perfectly fine...
I am very uncomfortable at my current workplace because most of the group seem to be narcissistic, loud, rude, show offs, which I find difficult to handle. It's not my sort of sense of humour, they are also obsessed with status, success, it's really over the top and so I just accept that I am different and try to focus on the job..
Remember people have lots of ego and generally when they talk, it's about them, it's all about them and ego stroking, all the time, and you can tell because they are not good listeners, but are very good at talking about their own worlds and agendas, ideas...but they don't bring others into the conversation, it's generally about showing off.
My sense of humour is more based on non gossipy topics or people but on general observation, which I prefer....
So, remember that there are people who will accept you even if you are not as loud or as extroverted as others...
Don't put extroverts on a pedestal, yes, they have ego, yes they seem confident, but it's just a front.