Why do I feel complete dread knowing my fiancée is coming home from a two-week trip tomorrow?

My fiancée left for a two-week work conference across the country fourteen days ago. We’ve been together for five years, living together for three, and our wedding is scheduled for next summer. I was supposed to miss her, count the days, and text her constantly about how empty the apartment felt. i didn't miss her at all. For the past two weeks, I’ve felt a level of calm and relief I haven't experienced in years. The house stayed clean, I cooked whatever I wanted without hearing complaints, and I didn't spend every evening walking on eggshells managing someone else's bad mood or passive-aggressive comments. It was like a fog lifted from my brain. I realized that our entire relasionship is just me exhausting myself trying to keep her happy while slowly losing my own personality. I slept better, laughed more with my friends, and actually enjoyed waking up in the morning. She lands in eight hours and just texted me saying "can't wait to see you babe." My stomach immediately sank into my shoes. I’m sitting on our couch feeling sick because I know the second that front door opens, the suffocating weight is coming right back in. How do you tell someone you love that their absence was the best two weeks of your year?