Opportunity to achieve complete NC - why am I sad and scared?

Hello,

I have a job interview tomorrow. It's an interesting job, good location, and good for my career.

It will also allow me to achieve complete NC from XN, who is a colleague.

Why am I not ecstatic about this opportunity? Why do I feel sad and scared and PANICKED about leaving? Why is there a little part of me that wants to sabotage the interview?

I am very confused, and feel heartbroken all over again.

Thoughts?