Metaphorically speaking, our packed days and weeks are like avalanches, rolling over our heads and burying us underneath them. As in a real avalanche, the key lays in creating space. Space between the things, between the events.
To be single at heart, I think, means that you see yourself as single. Your life may or may not include the occasional romantic relationship, but you don't aspire to live as part of a couple for the long term.