Where do you draw the line?

Today I have been thinking a lot about 'self''.
What does that mean, to be one's self that is? I know that the term self can be used very loosely and it covers a wide variety of areas so i'll be a little bit more specific. I've been thinking about where to draw the line. I have found that in order to live in the world today and live with people, you have to let go of some of the aspects that contribute to 'self'. So where do you draw the line? Where does compromising, being flexible, and living with people begin to take a destructive toll on the definition of self.
I am one of those people who puts the interest, desires, needs, and requests of others above mine all the time. It is part of who I am. It makes me the compassionate, loving, caring person that I am. While it might be annoying a lot of the time, I have embraced it, love it, and would not be any different. However, lately I have been feeling 'drained'.
'drained' : 1. feeling of exhaustion.
2. feeling like you are giving so much of yourself and are not getting anything in return.
3. feeling of emptiness, frustration, loneliness and sometimes anger mostly as a result of unreached expectations by people you love, cherish, care so very deeply for.
I love to give, love to give of myself, I would do ANYTHING for the people I love the most in this world, I would give ENTIRELY of myself for the people who make my world what it is, I would put aside my interests WHOLEHEARTEDLY for my family, my friends, my better-half. But sometimes I find myself in this place feeling nothing but 'drained'.
So where do you draw the line?

Inspirational friends <3

Today can only very simply be termed as sad. After a long night, tears, puffy eyes, and a massive headache that lasted up until the late hours of this evening, it was great to talk to someone who would immediately raise my spirits. Rather than talk about this person, i'll write this blog to this person.
"You totally put the first real smile on my face today. You are right. Maybe all this mishap in my life is happening for a reason. In the midst of all my tears and worries I failed to take a moment to look at the silver lining in this dark cloud. You opened my eyes to see all the good that could possibly come out of me not getting acceptance into the MPH program. Thank you. I always knew there was a reason why you are a part of my life, a reason why that feeling of intense dislike that i first felt when i first met you changed quickly and has only seemed to grow in a very positive direction since then. Behind your jerk cover :) you are a very amazing person and definitely one my spiritually uplifting friends. Te amo always <3"
I now see the silver lining in this dark cloud because of my inspirational friend.