Why do i panic when she and i don't see eye-to-eye?

when things are "off" between us, its never really bad... its just a wierd vibe ~ its usually emotional and intense, but u can't put ur finger on it ~ like, she'd be upset about something i did but won't tell me, or i'd be upset about something she did and she can tell, but i won't say anything until i think it through ~ all at once we both feel that tension and we become stuck ~ we're always diplomatic and never argue ~ we love eachother very much and prefer being soft-spoken about how we feel instead of exploding on eachother ~ most of the time i worry and cry quietly to myself until i get a breakthrough ~ in a day or two the tension pes, then we're fine ~ but, at that moment of discontent i panic and quietly go crazy inside at the thought of losing her ~ why do i do that? ~ she says she's not going anywhere and i kinda know that automatically... even before a tense moment ~ still... I PANIC--any thoughts?