When Does a Running Break Turn into a Hiatus?

It's been 4 weeks since my last race. Granted, that race was a marathon. But since that race, I have ran twice. What?! Two times? I've changed my bed sheets more than I've run?! So my question: when does a break from running/racing turn into a hiatus? And more importantly, why is it so hard to start back up again? I know I can't be alone on this.