Just be aware that sending a DA letter is still playing by their rules. You can just leave and to hell with their process.
I have had this ill feeling for the past ten years, but lacked being true to myself. When you grow up in the "truth", its engraved into you that appearances are everything!
I know that feeling ... it really is like being in the matrix, knowing things aren't right but not having any other frame of reference to tell for sure "why".
When you leave, you have the freedom to see it all for what it really is.
The Matrix nailed it:
"I know *exactly* what you mean. Let me tell you why you're here. You're here because you know something. What you know you can't explain, but you feel it. You've felt it your entire life, that there's something wrong with the world. You don't know what it is, but it's there, like a splinter in your mind, driving you mad. It is this feeling that has brought you to me. Do you know what I'm talking about?"