"Before" and "After" are fine. "Behind" is not incorrect in the original text, but it can be terribly, frustratingly ambiguous. As you've noted, "I'm running b

"Before" and "After" are fine. "Behind" is not incorrect in the original text, but it can be terribly, frustratingly ambiguous. As you've noted, "I'm running behind" means "I'm running late," i.e. I will arrive after the correct time. But "My clock is running behind" means "My clock is running slow," meaning it shows a time before the correct time. Similarly, when projects are behind schedule (i.e. likely to complete after the correct time), we sometimes solve this by pushing the schedule back... Meaning by pushing the correct time into the future, as opposed to most contexts where "pushing something back" would mean "pushing it further behind." So we push schedules back to move deadlines forward. Personally, I usually use "into the future" and "into the past" to be precise. Treating time with spatial-positional-relative language is fraught with inaccuracies. (Fun fact: did you know "biweekly" means either "twice a week" or "once every other week?" I can't think of any other measurement unit that has a factor-of-four error built into its very definition).