(I kinda setup my own rules on changelings logic. So if there are any other changeling stories that have different logic, I won't follow it.)
[2nd POV] A changeling is a mindless slave, and was only born to serve Queen Chrysalis. It does not have feelings, so it does not feel remorse. A changeling cannot think or choose for itself, as it is not sentient. It only moves without question, and only constantly feed off of the love of ponies. Since it is not sentient, it cannot be befriended, cannot learn to communicate, and cannot feel love. Its sole-purpose is to feed off love out of every pony alive.
But... that doesn't seem to apply to you.
The day you met that one unicorn, was the day you began asking, questioning your own existence.
Ever since the fall of Queen Chrysalis, she was nowhere to be found. Your siblings can't seem to do anything without her guidance, and slowly, each one of your siblings begin to die out. As an endangered changeling in hiding, you use your newly discovered free-will and wits to try to find out the answer to your question. Trying to solve it before you die. "Who am I now?"
(I guess now that i think about it, I just made changelings the equivalent to zombies. And you are a.... Sentient zombie?)
On hiatus for the moment. Until I get my shit together, this story is going to just linger there for some moments.