Most people take on the characteristics of the people around them, whether they want to or not, and whether they care to admit it or not. They can't help themselves. It's in their genes. Since our species first crawled out of the primordial ooze, conformity has been an important aspect of survival. To conform meant to be accepted by others, and to survive to pass on your conformist genes to future generations. Die-hard individualists usually died, hard, and their individualist genes with them.
Go to work in a sawmill, and no matter how well spoken you were when you went in, by the time you come out, all the clever adjectives and adverbs that used to enhance your conversation will have been replaced by a single word that starts with F. Go to work in a health food store, and before you know it you'll be eating things you can't pronounce. Hang out with kids for a while and soon you'll be calling everyone "Dude". It's inevitable. It's the way the Universe works, and you can't change it.
So don't fight it. Work with it. Surround yourself with people you admire. People you respect. People you aspire to be. Go find them, wherever they are, and move there if you have to. The world is a big place, and you can go wherever you like. Wherever you have to. The choice is yours, and nobody else's. Don't let fear hold you back.
For most of us, the people we spend the most time with are the people we work with every day. So if you're not happy with who you are, take a look at who you work with. It might be time to start looking for another job.