Soulius is right it is just nature taking ts course.The people whom you associate with the most,their habits will rub off on you,it is only natural for it to happen.As the old folks say 'Show me your friends and I will tell you who you are'.
It talks about the MBTI personalities. But anyways, you could try meditating on your sense of self. Though the best advice IMO is to not care about how you act or who you act like, unless of course you are partaking in a detrimental action. Just be yourself and don't worry.