No sense of self (sent before finished writing title)

I have no sense of who I am and it's so hard to think I'll have to go through life like this. Whenever I'm with people I allow their personality to take over and I simply imitate them. Their values become my values, their mannerisms become my mannerisms. It's so hard to know that I have no identity. Can anyone relate? I wish I knew why I was like this.