I recently started calling myself aromantic after polling several friends about, specifically, their physical response to feeling "love." It took about 2 months and a therapy session to finally understand how I "feel" it, but its very similar to what you describe. I know I am "in love" when I feel safe. That means feeling safe enough to share my thoughts, my emotions, etc. whether that be with friends or with a partner (I was in a relationship during this.)
You're kind of hitting on that same feeling. You didn't say whether or not you "felt" love, but you felt safe to be open with someone.
Take it or leave it, but I identify as aro (still playing around with it, but pretty confident), soooo....I don't see why you couldn't call yourself aro.
