at what point do you cut ties?

ever since I went to college I've had to face the fact that there comes a point in time at which you say good-bye to the old and do your best to welcome the new, whether you're ready to or not. In college it was letting go of a first love, the security of parental involvement, and the friends that you have grown up with. Now, after graduating from college I find myself debating what to keep in my life and what to let go of. Life changes and people change, they grow or they become stagnant, and if you're not careful they'll prevent you from growing as well. That's how I feel about some of the people that i"ve kept so close for so long, and now I find myself questioning why? Especially if they aren't acknowledging who you are trying to be and helping you reach that goal. I've always believed that as a friend you should always support your friend in the form of friendship. You don't always have to agree with the decisions that they make, but you do have to let them knoe that no matter what you'll be there for them when they need you. Unfortunately I've come to realize that this point of view on friendship is only beneficial if the other half of the friendship feels that same way about his or her's duties in a friendship. If it's uneven, all you end up with is sitting back and allowing that person to take advatage of your loyalty. You can't be a hero to every one, and there is no way that you can please everyone. So I guess my conundrum is where do you draw the line between selflessness and self-preservation. How much do you give before you've given everything away and realize that you've given who you are just to make someone else happy? So where do you cut the ties, or I guess I should ask when?
I often feel like I have no identity, I have nothing that makes me me. I am who the person or people around me wants me to be at that time, and the realization of that makes me sick. I want so bad to be who i am, and yet can't get past the fear of rejection....rejection from family, friends, professors, the church. And all the while I've become so angry about the who situation that I"ve taken on a synnical lens of the world....and that makes me sad because that's not who i am. I am who i am, I beleive that I was shaped and formed this way for a reason. I guess I really need to learn the difference between conforming and adjusting. But just how much adjusting, and if someone is asking you to comform or requiring it of you in order to a part their life, and life that you ahve already promised to be a part of, is that when you cut the ties?Don't know if any that made sense, but I'm finding a little more clarity, a good thing, I think....